hot-dip galvanized steel sheet and manufacturing process

专利摘要:
abstract a hot-dip galvanizing layer or an alloyed hot-dip galvanizing layer is formed on the surface of a base steel sheet in which in volume fraction, 40 to 90% of a ferrite phase and 5% or less of a retained austenite phase are contained, and a ratio of non-recrystallized ferrite to the entire ferrite phase is 50% or less in volume fraction, and further a grain diameter ratio being a value of, of crystal grains in the ferrite phase, an average grain diameter in the rolling direction divided by an average grain diameter in the sheet width direction is 0.75 to 1.33, a length ratio being a value of, of hard structures dispersed in island shapes, an average length in the rolling direction divided by an average length in the sheet width direction is 0.75 to 1.33, and an average aspect ratio of inclusions is 5.0 or less. ******************************************** Translation of the patent summary summary of invention: "sheet of high-strength hot-dip galvanized steel that has excellent resistance to delayed fracture and method of manufacturing it". a hot dip galvanizing layer or an alloy hot dip galvanizing layer is formed on the surface of a base steel sheet in which the volume fraction, 40 to 90% of a ferrite phase and 5% or less of a phase of retained austenite are contained and a proportion of non-recrystallized ferrite to the entire ferrite phase is 50% or less by volume fraction and a grain diameter proportion being a value of average grain diameter in the lamination direction divided by an average grain diameter in the width direction of the sheet is 0.75 to 1.33, a length ratio being a value of, of hard structures dispersed in island shapes, a average length in the lamination direction divided by an average length in the width direction of the sheet is 0.75 to 1.33 and an average aspect ratio of inclusions is 5.0 or less.
公开号:BR112014007483B1
申请号:R112014007483
申请日:2012-09-28
公开日:2019-12-31
发明作者:Minami Akinobu；Murasato Akinobu；Ban Hiroyuki；Kawata Hiroyuki；Hiramatsu Kaoru；Maruyama Naoki；Yasui Takeshi；Kuwayama Takuya
申请人:Nippon Steel & Sumitomo Metal Corp；Nippon Steel Corp；
IPC主号:

专利说明:

Descriptive Report on the Patent of the Invention for HOT GALVANIZED STEEL SHEETS AND THE SAME MANUFACTURING PROCESS.
TECHNICAL FIELD [001] The present invention relates to a hot-dip galvanized steel sheet that uses a high-strength steel sheet that has a maximum tensile strength of approximately 900 MPa or more as a base material and that has a layer of hot-dip galvanizing formed on the surface of the high-strength steel sheet and particularly refers to a hot-dip galvanized steel sheet which has excellent delayed fracture resistance and at the same time, having excellent anisotropy of the delayed fracture resistance and a process manufacturing process.
BACKGROUND OF THE TECHNIQUE [002] In recent years, there has been an increasing demand for high-strength steel plates used for automobiles or construction machines and various parts and structures of other civil engineering structures etc. In relation to this background, the high strength steel sheet that has a maximum tensile strength of 900 MPa or more has been used mainly for shock reinforcement materials, impact protection bars etc. in automobiles.
[003] In addition, it is usually necessary that the steel sheets used for them have excellent resistance to corrosion because they are often used on the outside.
[004] As such steel sheets to be used in a field necessary for corrosion resistance, a hot-dip galvanized steel sheet obtained by carrying out hot-dip galvanizing on a surface of a base steel sheet can be widely used. In addition, recently, a plate was also widely used
Petition 870190028455, of March 25, 2019, p. 10/134
2/113 of hot-dip galvanized alloy steel obtained by carrying out, after hot-dip galvanizing, a treatment to obtain an alloy in which an electrodeposition layer is heated to a temperature equal to or higher than the melting point Zn to diffuse Fe in the electrodeposition layer inside the base steel plate, to thereby transform the electrodeposition into a layer composed mainly of a Zn-Fe alloy.
[005] In fact, when the high-strength steel plate is applied to a car or similar, it is necessary to solve a problem of delayed fracture.
[006] The delayed fracture is a phenomenon that when working or assembling a part, there is no crack or fracture, however while this part is in use under a situation where there is a great effort action, a fracture such as a crack occurs suddenly in a way that causes fragility hardly with the occurrence of plastic deformation in the external appearance. It is known that the delayed fracture is closely related to the entrance of hydrogen in a steel plate from the environment outside the steel plate. That is, it was generally believed that the delayed fracture was a weakening phenomenon that can be attributed to the entrance of hydrogen from the external environment to be diffused in steel.
[007] As a factor that greatly affects the delayed fracture, the strength of the steel sheet is known. This is because as the steel plate has greater resistance, it has a greater possibility of being used in an environment where a great effort acts. That is, when a low-strength material is used for a part on which there is a high effort action, the material is immediately plastically deformed to be fractured, so that the delayed fracture does not normally occur. On the other hand, plastic deformation and fracture do not occur easily in a material of great
Petition 870190028455, of March 25, 2019, p. 11/134
3/113 resistance, so that a highly resistant material is often used in an environment where there is a great deal of effort. In addition, in a steel product to be used after having been subjected to lime-forming work such as an automobile part, residual work effort occurs. This residual effort increases the greater the strength of the steel sheet. Therefore, in addition to its external load stress, a large residual stress is added to the steel sheet and thus it is likely that the delayed fracture will occur. As a result, when the material has a higher strength, there will be greater concern about the occurrence of a delayed fracture.
[008] On the other hand, a thin steel sheet, for example, is known that a thin steel sheet that has a sheet thickness of approximately 3.0 mm or less has anisotropy in delayed fracture resistance. That is, a difference in delayed fracture resistance is sometimes caused depending on the work direction (generally, the lamination direction in the final cold rolling or in the direction of the lamination width perpendicular to it) in a sheet fabrication process of steel. This trend becomes significant in a particular thin sheet. In this way, when a thin sheet of high strength steel is used for a part on which there is a high effort action, measures are taken to ensure safety. That is, measures were taken such that such a design is carried out so as not to cause delayed fracture also in the direction in which the delayed fracture resistance is the least or the direction in which the steel sheet is applied to a part is considered so work in the direction where the delayed fracture resistance is low can become light. However, such measures cause a problem that a significant restriction arises when using a steel plate.
Petition 870190028455, of March 25, 2019, p. 12/134
4/113 [009] Thus, as a property of the thin steel sheet itself, the development of a delayed thin steel sheet in which not only the fracture strength simply improves, but also the anisotropy of the delayed fracture strength is reduced it is intensely desired.
[0010] In fact, considering conventional techniques related to the anisotropy of a thin steel sheet, there are the following techniques. First, as a means of reducing ductility anisotropy to improve steel sheet properties, there is a technique illustrated in Patent Literature 1. In addition, as a means of reducing flexibility and toughness to improve steel sheet properties steel, there is a technique illustrated in Patent Literature 2. However, in both Patent Literature 1 and 2, delayed fracture resistance is not described and means for eliminating the anisotropy of delayed fracture resistance are not disclosed.
[0011] In addition, in Patent Literature 3, a steel plate has been described which has excellent delayed fracture resistance and which has small anisotropies of tensile strength and ductility. However, delayed fracture resistance anisotropy is not described and the means for reducing delayed fracture resistance anisotropy are also not disclosed.
[0012] In addition, as a method to improve the delayed fracture strength of a steel sheet, in Patent Literature 4 and Patent Literature 5, a steel sheet has been described in which the main phase of the steel sheet lies transformed into hard structures such as bainite, bainitic ferrite, martensite and tempered martensite to thereby improve the delayed fracture resistance. In addition, in Patent Literature 6, a steel sheet was described in which the main phase of the steel sheet turned into tempered martensite and then, in tempered martensite, fine carbide is dispersed to
Petition 870190028455, of March 25, 2019, p. 13/134
5/113 thereby improving the delayed fracture resistance.
[0013] However, in all steel sheets by these Patent Literature techniques 4 to 6, the structure that is hard and of low ductility is considered as the main phase, so that ductility is also low throughout steel sheet, resulting in the fact that it is unsuitable for use where the steel sheet is subjected to a molding job, to be used.
[0014] In Patent Literature 7, it has been described that in a surface layer within 10 pm of the steel sheet surface, oxides are dispersed and the oxides trap hydrogen to thereby improve the delayed fracture resistance of the steel sheet. In addition, in Patent Literature 8, a steel sheet was described in which the main phase of the steel sheet turned into ferrite, martensite being a hard structure dispersed in the steel sheet and by fine precipitates such as Ti, Nb and V, a martensite block size is thinned to thereby improve the delayed fracture strength. In addition, in Patent Literature 9, a steel sheet has been described in which, in addition to thinning the block size described above, a decarburized layer is formed that has a thickness of 0.5 pm or more in a superficial layer of the sheet steel to improve the delayed fracture resistance.
[0015] In Patent Literature 7 to 9, it has been reported that delayed fracture resistance is improved beyond resistance and ductility, however no attention has been paid completely to delayed fracture resistance anisotropy.
CITATION LIST
PATENT LITERATURE [0016] Patent Literature 1: Japanese Patent Publication
Open to public inspection N °. 2005-256020 [0017] Patent Literature 2: Japanese Patent Publication Open to public inspection No. 2010-156016
Petition 870190028455, of March 25, 2019, p. 14/134
6/113 [0018] Patent Literature 3: Japanese Patent Publication
Open to public inspection N °. 2010-168651 [0019] Patent Literature 4: Japanese Patent No. 3247907 [0020] Patent Literature 5: Japanese Patent No. 4317384 [0021] Patent Literature 6: Japanese Patent No. 4712882 [0022] Patent Literature 7: Japanese Patent Publication
Open to public inspection N °. 2007-211279 [0023] Patent Literature 8: Japanese Patent Publication
Open to public inspection N °. 2011-111671 [0024] Patent Literature 9: Japanese Patent Publication
Open to public inspection N °. 2011-111675
NON-PATENTARY LITERATURE [0025] Non-patent literature 1: HAYASHI, Kunio, four others Evaluation of Hydrogen Embrittlement Susceptibility for sheet steel Materia (The Japan Institute of Metals and Materials Periodical), March 20, 2005, 44 (3) , P. 254-256 [0026] Non-Patent Literature 2: The Iron and Steel Institute of Japan Production Technical Committee Surface-treated Steel Sheet Committee Edition, Manual: Hot-dip Galvanized Steel Sheet, The Iron and Steel Institute of Japan, January 1991 , P. 53-55
SUMMARY OF THE INVENTION
TECHNICAL PROBLEM [0027] As previously described, when, for example, steel sheet having a high strength of approximately 900 MPa or more, particularly a thin steel sheet having a thickness of approximately 3.0 mm or less is used as a part on which a large load acts, anisotropy of delayed fracture resistance becomes a problem. However, conventionally, the fact is that a reduction in the anisotropy of a mechanical property such as ductility other than resistance was considered
Petition 870190028455, of March 25, 2019, p. 15/134
7/113 delayed fracture resistance or measures to improve delayed fracture resistance itself, but a reduction in the anisotropy of delayed fracture resistance was not particularly considered. Therefore, as previously described, when applying to a part that has a large load, when trying to avoid the occurrence of delayed fracture for safety and stability, there was no choice, however to generate the restriction in terms of design or work. So, this problem was inevitably also caused in a hot-dip galvanized steel sheet obtained by forming a hot-dip galvanizing layer on a surface of a high-strength steel sheet to improve corrosion resistance and also in a steel sheet. hot-dip galvanized in alloy in which an alloy is obtained in the electrodeposition layer.
[0028] The present invention was carried out in the context of the above circumstances and aims to provide a hot-dip galvanized steel sheet in which although it is possible to guarantee ductility and strength, an improvement in delayed fracture strength is achieved and at the same time , the anisotropy of delayed fracture resistance, particularly anisotropy (anisotropy in the plane) of the delayed fracture resistance on a surface parallel to the surface of a plate (laminated surface) is reduced and additionally, to provide a method of fabricating it.
SOLUTION TO THE PROBLEM [0029] The present inventors have repeated several experiments and exams to discover a process to improve the delayed fracture resistance and reduce the anisotropy in the plane of the delayed fracture resistance without impairing the ductility and resistance of a base steel plate . As a result, they recently discovered that not only is a chemical composition of a properly adjusted base steel plate, but also a steel structure is
Petition 870190028455, of March 25, 2019, p. 16/134
8/113 adjusted appropriately and at the same time, specific phases and structures and inclusion formats are adjusted appropriately and also a surface layer of a base material becomes a decarburized layer in which the oxides are dispersed appropriately , thereby making it possible to solve the problems described above and discovered necessary manufacturing process conditions for that and completed the present invention.
[0030] Thus, the essential point of the present invention is as follows.
[0031] (1) A hot-dip galvanized steel sheet with high strength that has excellent delayed fracture resistance, includes: [0032] a base steel sheet made of steel that contains:
[0033]% by mass, [0034] C: 0.075 to 0.400%;
[0035] Si: 0.01 to 2.00%;
[0036] Mn: 0.80 to 3.50%;
[0037] P: 0.0001 to 0.100%;
[0038] S: 0.0001 to 0.0100%;
[0039] Al: 0.001 to 2.00%;
[0040] O: 0.0001 to 0.0100%;
[0041] N: 0.0001 to 0.0100%; and [0042] the rest being composed of Fe and unavoidable impurities and [0043] the hot galvanizing of the layer formed on the surface of the base steel plate, where [0044] in a range of 1/8 thickness up to 3 / 8 thick with the position of 1/4 thickness of the thickness plate of the base steel plate of a surface of the base steel plate being the center, a structure of the base steel plate is transformed into a structure in which they are contained 40 at 90% by volume fraction of a ferrite phase, a retained austenite phase is 5% or less in fraction of
Petition 870190028455, of March 25, 2019, p. 17/134
9/113 volume and still a proportion of non-crystallized ferrite for the entire ferrite phase is 50% or less in fraction of volume, [0045] a proportion of diameter of the grain of crystal grains in the ferrite phase in said plate base steel is 0.75 to 1.33, where said ratio of grain diameter is defined as the proportion of an average grain diameter in the direction of the rolling mill divided by an average grain diameter in the direction of the plate width and a length ratio of hard structures dispersed in island shapes in the ferrite phase is 0.75 to 1.33, where said length ratio is defined as an average length in the lamination direction divided by an average length in the direction of the width of the sheet of the said structures and also an average aspect ratio of inclusions contained in the base of the steel sheet is from 1.0 to 5.0 and [0046] a superficial layer of the base steel sheet has become a layer d scarburized which has a thickness of 0.01 to 10.0 pm and also an average grain diameter of the oxides in the decarburized layer is 30 to 500 nm and an average density of the oxides in the decarburized layer is in a range of 1.0 χ 10 ¹² oxides / m ² up to 1.0 χ 10 ¹⁶ oxides / m ² .
[0047] (2) The high-strength hot-dip galvanized steel sheet that has an excellent fracture-retardant strength according to (1), where the base steel sheet also contains, by weight, one species or two or more species selected from [0048] Cr: 0.01 to 2.00%, [0049] Ni: 0.01 to 2.00%, [0050] Cu: 0.01 to 2.00%, [0051] Mo: 0.01 to 2.00%, [0052] B: 0.0001 to 0.0100% and [0053] W: 0.01 to 2.00%.
[0054] (3) High-strength hot-dip galvanized steel sheet
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10/113 which has excellent delayed fracture strength according to (1), where [0055] the base steel plate also contains,% by mass, one species or two or more species selected from [0056] Ti: 0.001 to 0.150%, [0057] Nb: 0.001 to 0.100% and [0058] V: 0.001 to 0.300%.
[0059] (4) The high-strength hot-dip galvanized steel sheet which has excellent delayed fracture strength according to (1), where the base steel sheet also contains 0.0001 to 0.0100% by weight in total of one species or two or more species selected from Ca, Ce, Mg, Zr, La and REM.
[0060] (5) High-strength hot-dip galvanized steel sheet that has excellent fracture-retardant strength according to (1), where on the base steel sheet, an average hardening coefficient per work (n value) in a range where the total elongation of 3 to 7% is 0.060 or more.
[0061] (6) The high-strength hot-dip galvanized steel sheet which has excellent fracture-retarded strength according to (1), in which in the base steel sheet, a limit diffusible hydrogen content value in the direction of lamination divided by a limit diffusible hydrogen content in the direction of the plate width is in the range of 0.5 to 1.5.
[0062] (7) The high-strength hot-dip galvanized steel sheet that has excellent delayed fracture strength according to (1), in which on the base steel sheet, a proportion of random X-ray intensity of BCC iron in the 1/4 thickness of a surface is 4.0 or less.
[0063] (8) The high-strength hot-dip galvanized steel sheet which has excellent fracture-retardant strength according to
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11/113 (1), where the hot dip galvanizing layer is one that has been subjected to an alloying treatment.
[0064] (9) A hot-dip galvanized steel sheet manufacturing process that has excellent delayed fracture resistance, includes:
[0065] a hot rolling step in which a plate containing:
[0066]% by mass, [0067] C: 0.075 to 0.400%;
[0068] Si: 0.01 to 2.00%;
[0069] Mn: 0.80 to 3.50%;
[0070] P: 0.0001 to 0.100%;
[0071] S: 0.0001 to 0.0100%;
[0072] Al: 0.001 to 2.00%;
[0073] O: 0.0001 to 0.0100%;
[0074] N: 0.0001 to 0.0100% and [0075] a remainder that is composed of Fe and unavoidable impurities is heated up to 1080 ^o C or higher, hot rolling is started, the total number of passes ( -) from the start of the hot rolling mill to the hot finish rolling mill is set to N, a rolling temperature ( ^o C) on the umpteenth pass is adjusted to TPi and a reduction ratio (-) on the umpteenth pass is adjusted to ri, hot rolling is carried out in such a way that N, TPi and ri satisfy Expression A below and the hot rolling is finished when the temperature of a base steel plate is a temperature in the range of 850 to 980 ^o Ç;
[0076] a primary cooling step in which a period of time from the hot finish rolling to the start of cooling is set to 1.0 seconds or longer, the hot rolled steel base plate is mainly cooled to
Petition 870190028455, of March 25, 2019, p. 20/134
12/113 a cooling rate of not less than 5 ° C / s or more than 50 ° C / if primary cooling is stopped when the base steel sheet temperature is a temperature in the range of 500 to 650 ° C ; [0077] subsequent to the primary cooling step, a secondary cooling step in which the base steel plate is cooled slowly in such a way that a period of time has elapsed before the temperature of the base steel plate becomes 400 ° C since the temperature at the time of the primary cooling which is interrupted takes an hour or a longer time and is cooled secondarily;
[0078] after secondary cooling, the cold rolling stage of the base steel plate by adjusting the total reduction ratio from 30 to 75%;
[0079] after cold rolling, an annealing step in which the temperature is increased in such a way that an average increasing rate of temperature in the range of 600 to 750 ° C becomes 20 ° C / s or less, the plate cold-rolled base steel is heated to a temperature of 750 ° C or higher and subsequently the heated base steel sheet is cooled in such a way that an average cooling rate in the range of 750 to 650 ° C becomes 1, 0 to 15.0 ° C / s and [0080] an electroplating step for performing hot dip galvanizing on the surface of the base steel plate obtained after the annealing step.
[Numeric expression 11
N
0.10s £ 1.00xlO ^lo xeKp <j- _T f-1 f
2.44 xlG ⁴ (7 ^ · + 273)
J Ϊ I
(] 543-7p7) ^ ^{IO () x] 0} · (Expression A) [0081] (10) The process of manufacturing a high-strength hot-dip galvanized steel sheet that has excellent strength
Petition 870190028455, of March 25, 2019, p. 21/134
13/113 delayed fracture according to (9), in which the annealing step and the electrodeposition step are carried out continuously by a continuous annealing and electrodeposition line that has a preheating zone, a reduction zone and a electrodeposition and still at least part of the preheat zone is adjusted to an oxidation treatment zone in which a proportion of air which is a value of the volume of air contained in a mixed gas per unit volume, than a mixed air gas used for a burner for heating and combustion of gas, divided by the volume of air theoretically necessary to cause complete combustion of the flue gas contained in the mixed gas per unit volume is 0.7 to 1.2 and in the oxidation treatment zone , oxides are generated in a part of the base layer of the base steel plate obtained after cold rolling and then in the reduction zone where a partial pressure ratio P (H ₂ O) / P (H ₂ ) which is a value of a partial pressure of water vapor divided by a partial pressure of hydrogen is 0.0001 to 2.0, the oxides are reduced and then in the electrodeposition zone, the base steel sheet that passed through the reduction zone is immersed in a hot dip galvanizing bath with the electrodeposition bath temperature set at 450 to 470 ° C and an effective amount of Al in the electrodeposition bath adjusted to 0.01 up to 0.18% by mass, with the proviso that the temperature of the steel plate at the time of the entry of the electrodeposition bath is from 430 to 490 ° C and thus hot-dip galvanizing is carried out on the surface of the base steel plate.
[0082] (11) The manufacturing process of high-strength hot-dip galvanized steel sheet that has excellent delayed fracture resistance according to (9), also includes:
[0083] After the electrodeposition step, a treatment step with formation of an alloy to form an alloy with the layer of the
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14/113 hot dip galvanizing.
ADVANTAGE EFFECTS OF THE INVENTION [0084] According to the present invention, as a hot-dip galvanized steel sheet using high-strength steel sheet as a base material, it is possible to obtain hot-dip galvanized steel sheet which has excellent delayed resistance to fracture and has little anisotropy of delayed fracture strength despite being a thin sheet without conferring ductility and strength. In this way, even when the high-strength hot-dip galvanized steel sheet of the present invention is used as a part on which a large load acts as a thin sheet, great security can be guaranteed and there is a small risk that the sheet high-strength hot-dip galvanized steel is subject to restrictions in terms of design and work and in this way it is possible to increase the degree of freedom of design and work to expand a range of application of high-strength hot-dip galvanized steel sheet.
DESCRIPTION OF MODALITIES [0085] Hereinafter, an embodiment of the present invention will be explained in detail.
[0086] A highly resistant hot-dip galvanized steel sheet of this modality is basically that the high-strength steel sheet that has a predetermined chemical composition and that has an appropriately adjusted steel structure is adapted as a base material and on the surface of the steel plate to be the base material, a layer of hot dip galvanizing is formed. Incidentally, the hot-dip galvanizing layer on the surface of a base steel plate can also be one that undergoes an alloying treatment after being subjected to hot-dip galvanization (a hot-dip alloy layer). In this case, the thicknesses of the hot-dip galvanized steel sheet
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15/113 resistance of this modality and of the steel plate to be the base material are not limited in particular, but in general, it is likely that an anisotropy of delayed fracture resistance will occur in the steel plate that has a thin plate thickness, so that an effect of the present invention is also increased when the thickness of the base steel plate is small. Thus, it is appropriate to apply the present invention to the case where the base steel sheet is a thin sheet. In particular, the high-strength hot-dip galvanized steel sheet thickness plate is preferably 0.6 to 5.0 mm. That is, when the thick sheet of the high-strength hot-dip galvanized steel sheet becomes less than 0.6 mm, it becomes difficult to keep the shape of the steel sheet flat. On the other hand, when the thickness sheet of the high-strength hot-dip galvanized steel sheet exceeds 5.0 mm, it becomes difficult to uniformly cool the interim part of the steel sheet. In addition, the base steel plate thickness plate is preferably 3.0 mm or less and more preferably 2.0 mm or less.
[0087] In this modality, a hot-dip galvanized steel sheet is manufactured which has excellent strength capable of achieving a safe reduction in anisotropy of delayed fracture strength and simultaneously with sufficient improvement of the delayed fracture strength while maintaining ductility (forming moldability) ) and resistance from (a) to (f) below.
(a) transforming a main body of a microstructure of a steel structure of the base steel plate into a soft ferrite phase.
(b) limiting the non-crystallized ferrite of the ferrite phase to a small amount and, at the same time, controlling an austenite phase maintained at a small amount.
(c) controlling a proportion of grain diameter that
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16/113 has a value of crystal grains in the ferrite phase, a grain diameter in the direction of the lamination divided by a grain diameter in the direction of the width of the plate to be in an appropriate range.
(d) controlling a length ratio that has an island-shaped hard structure value (island-shaped structure composed of an aggregate of hard phases such as mainly bainite, bainitic ferrite, martensite and tempered martensite), a length in the direction of the lamination divided by a length in the direction of the width of the plate to be in an appropriate range.
(e) controlling an average aspect ratio of inclusions (mainly Mn sulfides and / or coarse composite inclusions containing Mn sulfides) to be in an appropriate range.
(f) transforming a superficial layer of the base steel sheet into a relatively thick decarburized layer and dispersing oxides (oxides that mainly contain Si and / or Mn) in the finely and highly densely decarburized layer.
[0088] Then, reasons for limiting these conditions will be explained.
[0089] First, reasons for limiting a chemical composition of a steel sheet to be used as the base material of the high-strength hot-dip galvanized steel sheet of the present invention will be explained. Incidentally, in the following text,% means% by mass unless otherwise specified.
[C: 0.075 to 0.400% by weight] [0090] C is contained to increase the strength of a steel sheet. However, when the C content exceeds 0.400% by weight, the weldability of the steel sheet becomes insufficient. For the maintenance of weldability, the C content is preferably 0.300% in but
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17/113 sa or less and more preferably 0.250% by weight or less. On the other hand, when the C content is less than 0.075% by mass, the strength of the steel sheet decreases and it becomes difficult to guarantee the maximum tensile strength of 900 MPa or more. To further increase the strength of the steel sheet, the C content is preferably 0.085% by weight or more and more preferably 0.100% by weight or more.
[Si: 0.01 to 2.00% by weight] [0091] Si is an element that suppresses the generation of iron-based carbide in the steel plate and increases the strength and moldability of the steel plate. However, when the Si content exceeds 2.00% by weight, the steel sheet becomes brittle and the ductility deteriorates to create a possibility that cold rolling will become difficult to do. In view of ensuring ductility, the Si content is preferably 1.80% by weight or less and more preferably 1.50% by weight or less. On the other hand, when the Si content is less than 0.01% by mass, it becomes difficult to sufficiently disperse oxides in the decarburized layer. In view of this, the lower limit value of Si is preferably 0.20 wt% or more and more preferably 0.50 wt% or more.
[Mn: 0.80 to 3.50% by weight] [0092] Mn is added to increase the strength of the steel plate. However, when the Mn content exceeds 3.50% by weight, a concentrated part of coarse Mn occurs on a thick plate in the central part of the steel plate. As a result, the fragility of a plate occurs easily and a problem such as rupture of a shaped plate occurs easily. In addition, when the Mn content exceeds 3.50% by weight, weldability also deteriorates. Therefore, the Mn content needs to be 3.50% by weight or less. In order to guarantee weldability, the Mn content is preferably
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11/183
3.00% by weight or less and more preferably 2.70% by weight or less. On the other hand, when the Mn content is less than 0.80% by mass, a large amount of soft structures is formed during cooling after annealing and thus it becomes difficult to guarantee the maximum tensile strength of 900 MPa or more. Thus, the Mn content must be 0.80% by weight or more. To further increase the strength of the steel sheet, the Mn content is preferably 1.00% by weight or more and more preferably 1.30% by weight or more.
[P: 0.0001 to 0.100% by weight] [0093] P tends to segregate into a sheet in the central part of the thickness of a steel sheet and makes a weld zone brittle. When the P content exceeds 0.100% by weight, the weld zone becomes very brittle and thus the upper limit of the P content is adjusted up to 0.100% by weight. In addition, in view of this, the P content is more preferably 0.030% by weight or less. On the other hand, the adjustment of the P content to less than 0.0001% by mass is accompanied by a large increase in the manufacturing cost, so that 0.0001% by mass is adjusted as the value of the lower limit. Incidentally, the P content is more preferably 0.0010% by weight or greater.
[S: 0.0001 to 0.0100% by weight] [0094] S adversely affects weldability and workability during casting and hot rolling. In this way, the upper limit value of the S content is adjusted to 0.0100% by weight or less. In addition, S binds to Mn to form coarse MnS and decreases ductility and deformability by stretching the steel sheet, so that an S content is preferably established up to 0.0050% by weight or less and more preferably established up to 0.0030% by weight or less. However, the adjustment of the S content even less than
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0.0001% by mass is accompanied by a large increase in manufacturing cost, so that 0.0001% by mass is adjusted as the lower limit value. Incidentally, the S content is preferably 0.0005 mass% or more and more preferably 0.0010 mass% or more.
[Al: 0.001 to 2.00% by weight] [0095] Al suppresses the generation of iron-based carbide to increase the strength and moldability of the steel plate. However, when the Al content exceeds 2.00% by mass, the weldability gets worse and thus the upper limit of the Al content is adjusted up to 2.00% by mass. In addition, in view of this, the Al content is preferably adjusted to 1.50% by weight or less and more preferably adjusted to 1.20% by weight or less. On the other hand, the effect of the present invention is exhibited without particularly adjusting the lower limit of the Al content. However, Al is an inevitable impurity existing in the material in very small quantities and the adjustment even less than 0.001% by mass is accompanied by a big increase in manufacturing cost. In this way, the Al content is adjusted to 0.001% by weight or more. In addition, Al is an effective element as a deoxidizing material, so that to obtain the deoxidizing effect more sufficiently, the Al content is preferably adjusted to 0.010% by weight or more.
[N: 0.0001 to 0.0100% by weight] [0096] N forms a coarse nitride and deteriorates the ductility and deformability by stretching the steel sheet and thus its added quantity needs to be suppressed. When the N content exceeds 0.0100% by mass, this trend becomes significant, so that an upper limit on the N content is adjusted up to 0.0100% by mass. In addition, N causes the generation of defects during welding and therefore less is better. The effect of this
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20/113 invention is displayed without particularly adjusting the lower limit of the N content, however adjusting the N content to less than 0.0001% by mass causes a large increase in the manufacturing cost and therefore the lower limit is adjusted up to 0.0001% by mass or more.
[O: 0.0001 to 0.0100% by weight] [0097] O forms an oxide and deteriorates the ductility and deformability by stretching the steel sheet and thus its content needs to be suppressed. When the O content exceeds 0.0100% by weight, the deterioration of the deformability by stretching the steel sheet becomes significant and thus the upper limit of the O content is adjusted to 0.0100% by weight. In addition, the O content is preferably 0.0070% by weight or less and more preferably 0.0050% by weight or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the O content, however the adjustment of the O content to less than 0.0001% by mass is accompanied by a large increase in the cost of manufacture and, therefore, 0 .0001% by weight is adjusted to the lower limit of the O content. In addition, in view of the cost of manufacture, the O content is preferably 0.0003% by weight or more and more preferably 0.0005% in bulk or more.
[0098] In addition, one species or two or more species of elements selected from Cr, Ni, Cu, Mo, B and W can also be added to the base steel plate of the hot-dip galvanized steel plate. in this mode when necessary. The reasons for adding these elements are as follows.
[Cr: 0.01 to 2.00% by weight] [0099] Cr suppresses the phase transformation at high temperature and is an effective element to achieve a high strength of a steel plate. In this way, Cr can also be added to a plate instead of part of C and / or Mn. When the Cr content exceeds
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21/113 der 2.00% by mass, the moldability of the plate in a hot rolling step is impaired and productivity decreases and thus the Cr content is adjusted up to 2.00% by mass or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the Cr content, however the Cr content is preferably 0.01% by weight or more to obtain sufficiently the effect of achieving high strength of a steel plate by adding Cr.
[Ni: 0.01 to 2.00% by weight] [00100] Ni suppresses the phase transformation at high temperature and is an effective element to achieve high strength of a steel plate. In this way, Ni can also be added to the plate instead of part of C and / or Mn. When the Ni content exceeds 2.00% by mass, the weldability of the steel plate is impaired and thus the Ni content is adjusted to 2.00% by mass or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the Ni content, however the Ni content is preferably 0.01% by weight or more to obtain sufficiently the effect of achieving great strength of a steel plate by adding Ni.
[Cu: 0.01 to 2.00% by weight] [00101] Cu is an element that increases the strength of a steel sheet due to the existence of fine particles in steel. In this way, Cu can be added to the plate instead of part of C and / or Mn. When the Cu content exceeds 2.00% by mass, the weldability of the steel plate is impaired and thus the Cu content is adjusted to 2.00% by mass or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the Cu content, however the Cu content is preferably 0.01% by weight or more to obtain sufficiently the effect of making the resistance of a metal plate high. steel by adding Cu.
[Mo: 0.01 to 2.00% by weight]
Petition 870190028455, of March 25, 2019, p. 30/134
22/113 [00102] Mo suppresses the phase transformation at high temperature and is an effective element in making the strength of a steel plate high. In this way, Mo can also be added to the plate instead of part of C and / or Mn. When the Mo content exceeds 2.00% by weight, the moldability of the plate in the hot rolling step is impaired and productivity decreases, so that a Mo content is adjusted up to 2.00% by weight or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the Mo content, however the Mo content is preferably 0.01% by weight or more to obtain sufficiently the effect of making the strength of a sheet metal high. steel by the addition of Mo.
[W: 0.01 to 2.00% by weight] [00103] W suppresses the phase transformation at high temperature and is an effective element in making the strength of a steel plate high and can also be added to the plate instead part of C and / or Mn. When the W content exceeds 2.00% by weight, the moldability of the plate in the hot rolling step is impaired and the productivity decreases, so that a W content is preferably 2.00% by weight or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the W content, however the W content is preferably 0.01% by weight or more to sufficiently achieve the effect of achieving a high strength of a sheet of steel. steel by W.
[B: 0.0001 to 0.0100% by weight] [00104] B suppresses the phase transformation at a high temperature and is an effective element in making the strength of a steel plate high. In this way, B can also be added to the plate instead of part of C and / or Mn. When the B content exceeds 0.0100% by mass, the moldability of the plate in the hot rolling step is impaired and the productivity decreases, so that a B content is adjusted up to 0.0100% by mass or less, in view of productivity,
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23/113 the B content is more preferably 0.0050% by weight or less and even more preferably 0.0030% by weight or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the B content, however the B content is preferably adjusted to 0.0001% by weight or more to sufficiently obtain the effect of making the strength of a sheet of steel high. steel by adding B. To further increase the strength of a steel sheet, the B content is more preferably 0.0003% by weight or greater and even more preferably 0.0005% by weight or greater.
[00105] In addition, a species or two or more species of elements selected from Ti, Nb and V can also be added to the base steel plate of a hot-dip galvanized alloy steel plate of this modality when necessary. The reasons for adding these elements are as follows.
[Ti: 0.001 to 0.150% by weight] [00106] Ti is an element that contributes to increase the resistance of a steel plate by displacing the reinforcement by reinforcing the precipitate, reinforcing the fine grain by suppressing the growth of ferrite grains and suppression of recrystallization. However, when the Ti content exceeds 0.150% by weight, the carbonitride precipitation increases and the steel sheet's moldability deteriorates and thus the Ti content is adjusted to 0.150% by weight or less in order to guarantee the moldability of the steel sheet, the Ti content is more preferably 0.100% by weight or less and even more preferably 0.070% by weight or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the Ti content, however the Ti content is preferably 0.001% by weight or greater to sufficiently increase the strength of the steel sheet by adding Ti To be able to also increase the strength of a steel wool, the Ti content is more preferably 0.010% in
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24/113 mass or more and even more preferably 0.015 mass% or greater.
[Nb: 0.001 to 0.100% by weight] [0057] Nb is an element that contributes to increase the resistance of a steel plate by displacing the reinforcement by reinforcing the precipitate, reinforcing the fine grain by suppressing the growth of crystal grains of ferrite and suppression of recrystallization. However, when the Nb content exceeds 0.100% by weight, the carbonitride precipitation increases and the moldability of the steel sheet deteriorates and thus the Nb content is adjusted to 0.100% by weight or less in order to guarantee the moldability of the steel sheet, the Nb content is more preferably 0.050% by weight or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the Nb content, however the Nb content is preferably 0.001% by weight or greater to sufficiently obtain the effect of increasing the strength of the steel sheet by adding Nb . To further increase the strength of a steel plate, the Nb content is preferably 0.010% by weight or greater.
[V: 0.001 to 0.300% by weight] [0058] V is an element that contributes to increase the resistance of a steel plate by displacing the reinforcement by reinforcing the precipitate, reinforcing the fine grain by suppressing the growth of crystal grains of ferrite and suppression of recrystallization. However, when the V content exceeds 0.300% by weight, the carbonitride precipitation increases and the steel sheet's moldability deteriorates and thus the V content is adjusted to 0.300% by weight or less in order to guarantee the moldability of the steel sheet, the V content is more preferably 0.200% by weight or less and even more preferably 0.150% by weight or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the content of V, po
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25/113 r the V content is preferably 0.001% by weight or more to sufficiently obtain the effect of increasing the strength of the steel sheet by adding V.
[0059] In addition, like other elements, 0.0001 to 0.0100% by weight in total of one species or two or more species of Ca, Ce, Mg, Zr, La and REM can also be added to the steel plate based on a hot-dip galvanized alloy steel sheet of this modality. The reasons for adding these elements are as follows.
[0060] Ca, Ce, Mg, Zr, La and REM are effective elements to improve the moldability of a steel plate and a species or two or more species of them can be added to the plate. However, when the total content of one species or two or more species of Ca, Ce, Mg, Zr, La and REM exceeds 0.0100% by mass, there is a risk that the ductility of a steel sheet will be impaired when contrary. Therefore, the total content of the respective elements is preferably 0.0100% by weight or less. The effect of the present invention is exhibited without particularly adjusting the lower limit of the content of one species or two or more species of Ca, Ce, Mg, Zr, La and REM, however the total content of the respective elements is preferably 0 , 0001% by mass or more to sufficiently obtain the effect of improving the steel sheet's moldability in view of the steel sheet's moldability, the total content of one species or two or more species of Ca, Ce, Mg, Zr, La and REM is more preferably 0.0005 mass% or more and even more preferably 0.0010 mass% or more.
[00107] It is observed that REM represents Rare Earth Metal and refers to an element that belongs to the series of lantanoids. In this modality, REM or Ce is often added in misch metal and may contain elements from the lantanoid series other than La and Ce in the form of a complex. The effect of the present invention is displayed even when the elements of the lantanoid series other than La and Ce are
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26/113 contained in the plate as unavoidable impurities. In addition, the effect of the present invention is exhibited even when the metals La and Ce are added to the plate.
[00108] The rest other than the respective elements above the base steel plate need only be adjusted to Fe and unavoidable impurities. Incidentally, a very small amount of each of Cr, Ni, Cu, Mo, W, B, Ti, Nb and V described above that is less than the lower limit value described above is left to be contained as an impurity. In addition, in relation to Ca, Ce, Mg, Zr, La and REM in the same way, a small amount of them being allowed to be less than the lower limit described above of their total content is allowed to be contained as an impurity.
[00109] Next, a structure of the high-strength steel sheet to be used as the base material for the high-strength hot-dip galvanized steel sheet of this modality will be explained.
[00110] The structure of the high-strength steel sheet to be used as the base material of the high-strength hot-dip galvanized steel sheet of this modality is adjusted that like its microstructure, in a range of 1/8 thickness up to 3 / 8 thick with the position of 1/4 thickness of the thickness of a steel plate on the surface of the steel plate being the center, 40 to 90% by volume fraction of a ferrite phase are contained and the austenite maintained is controlled up to 5% or less in volume fraction. Then, the ferrite phase is adjusted so that a proportion of non-crystallized ferrite to the entire ferrite phase is controlled up to 50% or less in fraction by volume.
[00111] In this case, the reason why the structure in the range of 1/8 thickness up to 3/8 thickness with the position of 1/4 thickness of the steel plate thickness plate of a steel plate surface which is the center is controlled is because the structure in this range
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27/113 can be considered as one that represents the structure of the entire steel sheet except for the decarburized layer in the layer part of the steel sheet surface. That is, this is because as long as the structure described above is formed in this band, the entire steel sheet except for the decarburized layer in the surface layer part of the steel sheet can be determined to be the structure described above.
[00112] As described above, the structure containing a large amount of ferrite is adjusted and at the same time, the proportion of non-crystallized ferrite contained in the ferrite phase is controlled up to 50% or less in fraction of in volume and also austenite retained is controlled to be small in quantity and in this way it is possible to achieve the high strength steel sheet whose delayed fracture resistance is improved while ensuring good ductility. Then, there will be reasons explained below to limit these structural conditions.
[Ferrite: 40 to 90%] [00113] Ferrite is an effective structure to improve the ductility of the steel sheet and 40 to 90% by volume fraction must be contained in the steel sheet structure. When the volume fraction of ferrite is less than 40%, there is a risk that sufficient ductility of the steel sheet cannot be obtained. The volume fraction of ferrite contained in the steel sheet structure is more preferably 45% or more and even more preferably 50% or more in view of the ductility of the steel sheet. On the other hand, ferrite is a soft structure, so that when its volume fraction exceeds 90%, there is a risk that a sufficient strength of a steel sheet cannot be obtained. To sufficiently increase the strength of the steel sheet, the volume fraction of ferrite contained in the steel sheet structure is preferably adjusted up to 85% or less and more preferably. Petition 870190028455, of 03/25/2019, pg. 36/134
11/28 te adjusted up to 75% or less.
[Retained austenite: 5% or less] [00114] Retained austenite is transformed into very hard martensite during work to dramatically increase the work hardening capacity, so that this is an effective structure for improving the strength and ductility of steel plate and may be contained in the steel plate. However, the very hard martensite transformed by the retained austenite significantly promotes the delayed fracture of the steel sheet caused by the entry of hydrogen, thereby deteriorating the delayed fracture resistance. For this reason, the upper limit of the volume fraction of retained austenite is adjusted up to 5.0% or less. In addition, in view of this, the fraction by volume of austenite retained is preferably adjusted to 3.0% or less and can be 0%.
[00115] In this case, the volume fraction of retained austenite can be measured as follows.
[00116] That is, the X-ray analysis is performed on an observation surface that is a surface in the position of 1/4 thickness of the base steel plate thickness of a base steel plate surface and is parallel to the plate surface of the base steel plate. Then, from a result of it, a fraction of austenite area retained on the observation surface is calculated. In this modality, this fraction of area is considered as the fraction in volume of austenite retained at 1/8 of thickness up to 3/8 of thickness with the position of 1/4 of thickness of the thickness plate of the base steel plate of the surface of the base steel plate which is the center. Incidentally, the viewing surface can be adjusted to an arbitrary position from 1/8 thick to 3/8 thick as long as it is parallel to the plate surface of the base steel plate.
[Non-crystallized ferrite: 50% or less up to the entire ferrite phase]
Petition 870190028455, of March 25, 2019, p. 37/134
29/113 [00117] Ferrite includes three species: recrystallized ferrite in which recrystallization was caused in an annealing step; non-crystallized ferrite in which no recrystallization was caused and crystal orientations after the cold lamination and transformed ferrite that was once inverted transformed into austenite in an annealing step before the phase was transformed into ferrite.
[00118] Among them, non-crystallized ferrite is not preferable because the orientations of the crystal are deflected by cold rolling to increase the anisotropy of the steel sheet. In view of this, the proportion of non-crystallized ferrite for the entire ferrite is adjusted to less than 50% by volume fraction. In addition, within the non-crystallized ferrite, there are many displacements and / or displacement substructures, so that the existence of a large amount of non-crystallized ferrite causes a decrease in the ductility of the steel sheet. In view of this, the volume fraction of non-crystallized ferrite in the steel plate needs to be decreased, the volume fraction of non-crystallized ferrite for the entire ferrite is preferably adjusted to less than 30% and more preferably adjusted to less than 15%. The smallest volume fraction of non-crystallized ferrite is more preferable and can also be 0%.
[00119] In this case, the volume fraction of non-crystallized ferrite can be measured as follows.
[00120] That is, the non-crystallized ferrite has a characteristic that a crystal orientation varies in a single crystal grain because there are many displacements and / or displacement substructures within the non-crystallized ferrite. In addition, bainite, bainitic ferrite, martensite and tempered martensite made up of BCC iron crystal other than ferrite each have many displacements and / or displacement substructures in there similar to non-crystallized ferrite, so that they have a characteristic that an
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30/113 crystal orientation varies in a single crystal grain similarly. On the other hand, in each crystal grain of recrystallized ferrite and transformed ferrite, there is no wrong orientation of 1.0 ° or more.
[00121] For this characteristic, non-crystallized ferrite and other ferrites can be distinguished by performing high-resolution crystal orientation analysis using an EBSD (Electron Bach-Scattering Diffraction) method in a visual field in which FE-SEM observation was performed to measure structural fractions. Concretely, a surface that is in the position of 1/4 thickness of the base steel plate thickness plate of the base steel plate surface and is parallel to the plate surface of the base steel plate has a mirror finish and is subject to high resolution crystal orientation analysis using an EBSD method at a 0.5 pm measurement step. an erroneous crystal orientation between a proximity measurement point and each measurement point is obtained, each point that has an erroneous crystal orientation of 5.0 ° or more is ignored c as a point to be determined to belong to a different crystal grain and an average value of erroneous crystal orientations is obtained from a group of the remaining second proximity measurement points each having an erroneous 5.0 ° crystal orientation or smaller and determined to be in the same crystal grain. Then, it is possible that each of the points that has an average value less than 1.0 ° is determined to be recrystallized ferrite or transformed ferrite to obtain a fraction of their area. Then, by comparing the fraction of the area of the whole ferrite obtained by observation with FE-SEM and the fractions of the area of recrystallized ferrite and transformed ferrite, the fraction of the area of the non-crystallized ferrite and the proportion of the non-crystallized ferrite can be obtained for all the ferrite. In this
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31/113 modality, the fraction of the area of non-crystallized ferrite obtained in this way is considered as a fraction in volume of non-crystallized ferrite.
[Other steel structures] [00122] Like steel structures other than the ferrite phase described above (which includes non-crystallized ferrite) and the retained austenite, bainite, bainitic ferrite and martensite (tempered martensite or new martensite) are normally contained and also pearlite and coarse cementite are sometimes contained. The proportions of these structures are not particularly limited to preferably be controlled depending on the intended use. For example, a high yield ratio (= yield strength / tensile strength) is required on the steel sheet, the proportion (volume fraction) of bainite, bainitic ferrite, martensite, tempered martensite, perlite etc. it is preferably adjusted up to 40% or more in total. On the other hand, when it is necessary to improve the ductility of the steel sheet, the proportion (fraction by volume) of bainite, bainitic ferrite, martensite, tempered martensite, perlite, etc. it is preferably adjusted up to 40% or less in total.
[00123] Incidentally, as previously described, the proportion of each of the steel structures other than the ferrite phase (including non-crystallized ferrite) and the retained austenite phase is not particularly limited, but each preferable range and its ratio are as Next.
[New martensite: 40% or less] [00124] The new martensite is a structure to greatly improve the tensile strength. When the proportion of new martensite exceeds 40% by volume, the ductility of the steel plate deteriorates considerably. Therefore, the new martensite can also be contained in the base steel plate with 40% in volume fraction adjusted as the upper limit. To sufficiently increase resistance to
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32/113 traction of the steel plate, the volume fraction of new martensite is preferably adjusted up to 4% or more. On the other hand, new martensite becomes a fracture starting point to deteriorate toughness at low temperature, so that a fraction of the volume of new martensite is preferably adjusted up to 20% or less, more preferably adjusted up to 15% or smaller and even more preferably adjusted to 12% or less.
[Tempered Martensite: 50% or less] [00125] Tempered martensite is a structure to greatly improve the tensile strength of the steel sheet and does not easily become a starting point for steel sheet fracture, so that 50% or less in fraction by volume may also be conditioned in the structure of the steel plate. When the volume fraction of tempered martensite exceeds 50%, the ductility of the steel plate deteriorates considerably, which is not preferable.
(Bainitic and / or bainite ferrite: 60% or less) [00126] Bainitic ferrite and / or bainite are / are excellent structures without an excellent structure that contributes to a balance between the strength and ductility of the steel sheet and it can also be contained in the steel sheet structure in a volume fraction of 60% or less. In addition, bainitic ferrite and bainite are microstructures each having an intermediate resistance between soft ferrite and hard martensite and which has an intermediate resistance between tempered martensite and retained austenite. Thus, when used for the purpose of sophistication of the steel plate, these structures are both contained in the steel plate, to thereby decrease a large local difference within the steel plate and to provide a suppression effect of the occurrence of fracture. , which is preferable in view of the low temperature toughness. To sufficiently obtain this effect, the volume fraction of bainitic and / or bainite ferrite is
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33/113 preferably 10% or more and more preferably 15% or more. On the other hand, when the volume fraction of bainitic ferrite and / or bainite exceeds 60%, the ductility of the steel plate deteriorates, which is not preferable in view of ensuring the ductility of the steel plate, the volume fraction of bainitic ferrite and / or bainite is preferably adjusted to 50% or less and more preferably adjusted to 45% or less.
[00127] In addition, in the steel plate structure of the high strength adjusted as the base material in this modality, structures such as perlite and / or coarse cementite other than the one mentioned above can also be contained. However, when pearlite and / or coarse cementite are / are increased in the high strength steel plate structure, the flexibility of the steel plate deteriorates. Because of this, the volume fraction of perlite and / or coarse cementite contained in the steel sheet structure is preferably 6% or less and more preferably 4% or less in total.
[00128] The volume fractions of the respective structures contained in the high strength steel plate structure to be used as the base material in this modality can be measured by the following methods, for example.
[00129] X-ray analysis is performed on an observation surface that is 1/4 thickness of the base steel plate and is parallel to the surface of the base steel plate and from a result thereof, a fraction of area is calculated of retained austenite and this fraction of area can be considered as a fraction in volume of retained austenite. [00130] In this case, the volume fractions of the respective structures, namely, ferrite, bainitic ferrite, bainite, tempered martensite and new martensite can be obtained as follows.
[00131] First, a cross section parallel to the lamination direction of the base steel plate and perpendicular to the surface of the plate is
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34/113 adjusted as an observation surface and a sample is taken from it. Then, the observation surface is polished and attacked by nital. Next, the range of 1/8 thick to 3/8 thick with the position of 1/4 thick plate thickness of the base steel plate of a surface of the base steel plate being the center is observed by a field emission scanning electron microscope (FE-SEM: Field Emission Scanning Electron Microscope) to measure the area fractions of the respective structures and these area fractions can be considered as the volume fractions of the respective structures.
[00132] Furthermore, considering the steel plate to be used as the base material in this modality, (a) to (c) below are adjusted to reduce the anisotropy of the delayed fracture resistance.
(a) adjusting a grain diameter ratio which is a crystal grain value from the ferrite phase on a surface parallel to the sheet surface (laminated surface) of the steel sheet, a grain diameter in the direction of rolling divided by a diameter of the grain in the direction of the width of the plate (direction perpendicular to the direction of the lamination) (= a diameter of the grain in the direction of the lamination + a diameter of the grain in the direction of the width of the plate) to be in the range of 0.75 to 1, 33.
(b) adjusting a length ratio that is a value of a hard structure (hard phase) dispersed in an island shape on a surface parallel to the sheet surface (laminated surface) of the steel sheet, a length in the direction of the divided rolling mill by a length in the direction of the plate width (= a length in the direction of the lamination + a length in the direction of the plate width) to be in the range of 0.75 to 1.33.
(c) adjust an average aspect ratio of inclusions on the surface parallel to the plate surface (laminated surface) of the
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35/113 steel plate up to 5.0 or less. Hereinafter, the limiting reasons and methods of measuring them will be explained.
[Proportion of, of the ferrite phase crystal grains, a grain diameter in the direction of the lamination and a grain diameter in the direction of the plate width] [00133] When the ferrite crystal grains are extended in a specific direction in the surface parallel to the plate surface (laminated surface), anisotropy in the plane of delayed fracture strength is improved. Of the crystal grains of the ferrite phase, an average grain diameter in the lamination direction is adjusted to d (RD) and an average grain diameter in the direction of the plate width is adjusted to d (TD). When d (RD) / d (TD) then drops to 0.75, the delayed fracture resistance in the direction of the rolling of the steel sheet decreases in relation to the direction of the width of the sheet. Therefore, the proportion of the crystal grains in the ferrite phase, a grain diameter in the direction of the lamination and a grain diameter in the direction of the plate width, namely d (RD) / d (TD) is adjusted up to 0.75 or more. Incidentally, d (RD) / d (TD) is preferably 0.80 or more and more preferably 0.85 or more. Similarly, when d (RD) / d (TD) exceeds 1.33, the delayed fracture resistance in the direction of the rolling of the steel sheet decreases in relation to the direction of the width of the sheet. Therefore, 1.33 is adjusted up to the upper limit of d (RD) / d (TD). Incidentally, d (RD) / d (TD) is preferably 1.25 or less and more preferably 1.18 or less.
[00134] Incidentally, the measurement of grain diameters in the respective directions of crystal grains of the ferrite phase can be performed as follows.
[00135] That is, a surface that is 1/4 thickness of the base steel plate thickness of a base steel plate surface and is parallel to the base steel plate surface is corroded by nital and the surface is observed by an FE-SEM. The diameters of the
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36/113 grain in the lamination direction and in the direction of the plate width of each 100 to 1000 ferrite phase crystal grains that are chosen randomly in the observation are measured.
[Proportion of a hard structure in the shape of an island, a length in the direction of the lamination and a length in the direction of the width of the sheet] [00136] The hard structure is one in which the various crystal grains aggregate to exist in one island shape on a surface parallel to the sheet surface (laminated surface) of the steel sheet. When this hard island-like structure is extended in a specific direction on a surface parallel to the sheet surface (laminated surface) of the steel sheet, anisotropy in the plane of the delayed fracture resistance in the steel sheet is improved. Of the hard island-like structures on a surface parallel to the plate surface (laminated surface) of the steel plate, an average length in the direction of the rolling is adjusted to L (RD) and an average length in the direction of the plate width is adjusted up to L (TD). When L (RD) / L (TD) falls below 0.75, the delayed fracture resistance in the direction of the rolling of the steel plate decreases in relation to the direction of the width of the plate, so that a value of the structure lasts, the length in the lamination direction divided by the length in the direction of the sheet width, namely the value of L (RD) / L (TD) is adjusted up to 0.75 or more.
[00137] Incidentally, L (RD) / L (TD) is preferably 0.80 or more and more preferably 0.85 or more. Similarly, when L (RD) / L (TD) exceeds 1.33, the delayed fracture resistance in the direction of the steel sheet width decreases in relation to the rolling direction, so that 1.33 is adjusted up to the upper limit . L (RD) / L (TD) is preferably 1.25 or less and more preferably 1.18 or less.
[00138] Incidentally, the structure lasts in the shape of an island in this
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37/113 case means a hard structure in the shape of an island composed of an aggregate of hard phases such as bainite, bainitic ferrite, martensite and tempered martensite mainly, in other words, the structure in which plural crystal grains composed of harder phases of the that aggregate of ferrite to obtain an island shape to be dispersed in an original phase made of a phase of ferrite.
[00139] The measurement of the proportion of the length of the hard structure in the shape of an island can be performed as follows.
[00140] That is, first, the surface that is 1/4 of the thickness of the base steel plate thickness of the base steel plate surface and is parallel to the base steel plate surface has a mirror finish to be subject to to a high resolution crystal orientation analysis using an EBSD method at a 0.5 pm measurement step. Next, an erroneous crystal orientation is obtained between a second proximity measurement point and each measurement point, points each having an erroneous crystal orientation of 5.0 ° or less and determined to be in the same crystal grain. only extracted and an average value of erroneous crystal orientations of a group of points is obtained. Then, the points that each have an average value of 1.0 ° or more are mapped. The points that each have the average wrong crystal orientation of 1.0 ° or more are sometimes non-crystallized ferrite as well as the hard structure. Thus, after the crystal orientation analysis, the same visual field as that used for the crystal orientation analysis is corroded by nital and is observed by FE-SEM to obtain a dispersed ferrite state. Then, by comparing the dispersed state of ferrite and the result of the crystal orientation analysis, only hard structures can be extracted. In hard structures in the shape of 30 to 300 islands chosen at random from a hard structure in the shape of islands obtained as above, the
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38/113 lengths in the direction of rolling and in the direction of the width of the base steel plate and its proportion is obtained.
[Inclusion aspect ratio] [00141] An extended coarse Mn sulfide and / or a coarse composite inclusion containing Mn sulfide significantly deteriorates the delayed fracture strength of the steel sheet. When the average aspect ratio of inclusions exceeds 5.0, the delayed fracture strength of the steel sheet cannot be achieved sufficiently, so that it is necessary to adjust the average aspect ratio of inclusions contained in the base steel sheet up to 5.0 or less in order to ensure the delayed fracture resistance of the steel sheet, the average aspect ratio of inclusions is preferably 4.0 or less and more preferably 3.0 or less. The lower the aspect ratio, the more preferable it is and 1.0 is adjusted to the lower limit of the average aspect ratio of inclusions. Incidentally, the average aspect ratio of inclusions in this case means, when the two-dimensional shape of an inclusion is approximated to an ellipse, an ellipse value, a main axis divided by a minimum axis (= a main axis + minimum axis) .
[00142] Furthermore, since the coarse inclusions described above are each in a format selectively extended in a specific direction, the anisotropy of the delayed fracture resistance in the steel sheet becomes significantly strong. From inclusions on a surface parallel to the plate surface (laminated surface) of the steel plate, an average length in the rolling direction is adjusted to D (RD) and an average length in the direction of the plate width is adjusted to D (TD) . When D (RD) / D (TD) decreases to 0.50, the delayed fracture resistance in the direction of rolling of the steel plate deteriorates in relation to the direction of the width of the plate. On the other hand, when D (RD) / D (TD) exceeds 2.00, the delayed resistance to
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39/113 the thickness in the direction of the width of the steel plate deteriorates in relation to the rolling direction. To reduce the anisotropy of the delayed fracture resistance in the steel plate, D (RD) / D (TD) is preferably in the range of 0.5 to 2.0. The lower limit of D (RD) / D (TD) is preferably 0.60 or more and more preferably 0.70 or more. The upper limit of D (RD) / D (TD) is preferably 1.67 or less and more preferably 1.43 or less.
[00143] The average aspect ratio of inclusions can be obtained as follows.
[00144] That is, a cross section parallel to the rolling direction of the base steel sheet and perpendicular to the surface of the sheet is finished with a mirror as an observation surface. After that, using an FE-SEM, each of 10 to 100 inclusions that have a grain diameter of 2 pm or more is observed in a range of 1/8 thickness up to 7/8 thickness and a aspect ratio of each of them. Then, an average value is adjusted to an average aspect ratio. In addition, also in a cross section perpendicular to the rolling direction of the base steel plate and perpendicular to the plate surface, a similar observation is made and an average aspect ratio is obtained. The higher the average aspect ratio of the two is adjusted to the average aspect ratio of inclusions in the steel plate.
[00145] In addition, the length in the lamination direction of inclusions D (RD) can be obtained as follows.
[00146] That is, a cross section parallel to the rolling direction of the base steel plate and perpendicular to the surface of the plate is finished with mirror as an observation surface. After that, using an FE-SEM, each of 10 to 100 inclusions that has a grain diameter of 2 pm or more is observed in
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40/113 a range from 1/8 thick to 7/8 thick. Then, the length along the lamination direction of each of the observed inclusions is measured and an average value of the lengths is adjusted up to the length in the direction of the lamination of inclusions D (RD).
[00147] Similarly, in a cross section perpendicular to the rolling direction of the steel plate and perpendicular to the surface of the plate, the length of inclusions is obtained in the direction of the width of the inclusions plate D (TD).
[00148] Incidentally, when inclusions are observed, the analysis of the inclusion composition is performed using an X-ray energy dispersion spectrometer equipped with FE-SEM to confirm that all or some inclusions are Mn sulfides and the observation is fulfilled.
[Degree of deflection of crystal orientations] [00149] In addition, when the degree of deflection of crystal orientations in steel structures is high in the base steel plate, the anisotropy of the delayed fracture resistance in the steel plate is improved. That is, when the orientations of the ferrite crystal and hard structures (bainite, bainitic ferrite, martensite and tempered martensite) are curved in one or two or more specific directions, the anisotropy of the delayed fracture resistance in the steel plate is improved. Thus, in this modality, the degree of deflection of these structures is determined by a proportion of random X-ray intensity of BCC iron in the position of 1/4 thickness of the thickness plate of the base steel plate of a surface of the steel plate. base (a phase of a structure that has a cubic lattice structure centered on the body of the steel structure). Specifically, the proportion of random X-ray intensity is preferably controlled to 4.0 or less. One reason for this is as follows.
[00150] The structures described above are all made up of
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41/113 BCC iron crystals (crystals of a cubic lattice centered on the body). In this way, a texture of BCC iron crystals is measured by an X-ray diffraction method, thereby making it possible to assess the degree of deflection of the structures. The proportion of random intensity of BCC iron X-rays needs only to be obtained from an orientation distribution function (Orientation Distribution Function): which will be called ODF, hereinafter, which is calculated by an expansion method in series based on a large number of pole figures between pole figures {110}, {100}, {211} and {310} measured by X-ray diffraction and has a three-dimensional texture. Incidentally, the random X-ray intensity ratio is a numerical value obtained by measuring the X-ray intensities of a standardized sample that has no accumulation in a specific orientation and a sample for testing under the same conditions by an X-ray diffraction method or similar and dividing the X-ray intensity obtained from the test sample by the X-ray intensity of the standardized sample.
[00151] The manufacture of samples for X-ray diffraction is performed as follows. The steel sheet is polished to a predetermined position in the thickness direction of the sheet by mechanical polishing, chemical polishing or similar, to remove the stress by electrolytic polishing, chemical polishing or similar when necessary and at the same time, the sample is adjusted in a in such a way that the surface in the position of 1/4 thickness of the base steel plate thickness plate of a base steel plate surface becomes the measurement of the surface. Note that it is difficult to position the surface measurement at 1/4 thickness precisely. In this way, the sample only needs to be manufactured in such a way that the region within a range of 3% of the thickness plate with the target position (1/4 thickness of the steel plate thickness plate
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42/113 base of a base steel plate surface) with the center becoming a measurement surface. In addition, when X-ray diffraction measurement is difficult, a statistically sufficient number of measurements can also be performed using an EBSD method.
[00152] To sufficiently reduce the anisotropy of delayed fracture resistance, peak intensities are obtained over the respective cross sections at φ2 = 0 °, 45 °, 60 ° in the Euler space in the orientation distribution function described above ( ODF) and the maximum value of the peak intensities, the degree of deflection of the structure is evaluated. To sufficiently reduce the anisotropy of the delayed fracture resistance in the steel plate, the peak intensity is desirably adjusted to 4.0 or less. For the reduction in the anisotropy of the delayed fracture resistance in the steel plate, the lower peak intensity is more preferable and is more preferably adjusted to 3.5 or less and even more preferably adjusted to 3.0 or less. The lower limit of the peak intensity is not obtained in particular, however it is very difficult to adjust the peak intensity to less than 1.5 industrially, so that it is preferably adjusted to 1.5 or more.
[Decarburized layer] [00153] In this modality, to avoid the occurrence of delayed fracture caused by hydrogen to enter the surface of a steel plate, the microstructure of a part of the surface layer (surface layer) of the base steel plate is controlled. Concretely, to prevent the delayed fracture from starting with a part of the base layer of the base steel plate, the part of the base layer of the base steel plate is transformed into the decarburized layer whose hard structures are reduced and in the decarburized layer, thin oxides such as collection sites for hydrogen are dispersed in a very dense manner. In this modality, the diffusion of hydrogen from the
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43/113 inner part of the surface layer of the base steel plate is avoided in this way, to thereby improve the delayed fracture resistance of the steel plate. That is, (a) through (c) below are established.
(a) transforming the base layer of the base steel sheet into a decarburized layer that has a thickness of 0.01 to 10.0 pm.
(b) adjusting an average diameter of the oxide grain in the decarburized layer to 500 nm or less.
(c) causing the average density of oxides in the decarburized layer to be within a range of 1.0 χ 10 ¹² oxides / m ² to 1.0 χ 10 ¹⁶ oxides / m ² .
[00154] These limiting reasons are as follows.
[00155] The base steel sheet has the decarburized layer that has a sufficient thickness (layer whose hard structures are reduced) in the part of the superficial layer, to make it possible to suppress the delayed fracture starting in a part of the superficial layer. When the thickness of the decarburized layer is less than 0.01 pm, the delayed fracture in the surface layer part of the base steel plate is not suppressed, so that the thickness of the decarburized layer is adjusted to 0.01 pm or more. To sufficiently improve the delayed fracture resistance of the steel sheet, the thickness of the decarburized layer is preferably adjusted to 0.10 pm or more and more preferably to 0.30 pm or more. On the other hand, an excessively thick decarburized layer decreases the tensile strength and fatigue strength of a steel sheet. In view of this, the thickness of the decarburized layer is adjusted to 10.0 pm or less. In view of the fatigue strength, the thickness of the decarburized layer is preferably 9.0 pm or less and more preferably 8.0 pm or less.
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44/113 [00156] Inciderrally, the decarburized layer is a region that continues from a predominant surface of a base iron within the steel plate and indicates a region where the volume fraction of hard structure is equal to or less than the half of the volume fraction of the hard structure at the position of 1/4 thickness of the thickness of the base steel plate (the base iron part). In addition, the hard structure cited here indicates a structure composed of phases harder than ferrite, namely the structure composed of phases such as mainly bainite, bainitic ferrite, martensite, tempered martensite and retained austenite.
[00157] In addition, the thickness of the decarburized layer is determined as follows. That is, a measure of the surface obtained by mirror finishing of a cross section parallel to the rolling direction of the steel sheet and perpendicular to the surface of the sheet is observed using FE-SEM, the thickness of the decarburized layer is measured in three places or more on plain steel plate and an average thickness value is adjusted to the thickness of the decarburized layer.
[Oxides in the decarburized layer] [00158] The density and diameters of the oxide grain (oxides containing Si and / or Mn mainly) that exist in a dispersed manner in the decarburized layer of the steel plate also greatly affect the delayed fracture resistance of the plate of steel. That is, the oxides dispersed in crystal grains and / or at the limits of the crystal grain in the decarburized layer of a steel plate function as collection sites for external hydrogen to suppress the entrance of hydrogen on the inside of the steel plate, to thereby contribute to the improvement of the delayed fracture resistance of the steel sheet. As the density of the oxides is higher, the hydrogen inlet is suppressed, so that the density of the oxides is adjusted up to 1.0 χ 10 ¹² oxy
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45/113 of / m ² or more. In order to more sufficiently suppress the entry of hydrogen into the steel sheet, the density of the oxides is preferably adjusted to 3.0 χ 10 ¹² oxides / m ² or more and more preferably adjusted to 5.0 χ 10 ¹² oxides / m ² or more. On the other hand, when the oxide density exceeds 1.0 χ 10 ¹⁶ oxides / m ² , a distance between the oxides becomes excessively small, the part of the surface layer of the steel plate is broken by the action of light and the layer of electrodeposition on an external side of it is also broken. Therefore, the density of oxides is adjusted to 1.0 χ 10 ¹⁶ oxides / m ² or less. For the surface layer part of the steel plate to exhibit sufficient moldability, the oxide density is preferably adjusted to 5.0 χ 10 ¹⁵ oxides / m ² or less and more preferably adjusted to 1.0 χ 10 ¹⁵ oxides / m ² or less.
[00159] Furthermore, as the oxides to be dispersed in the part of the superficial layer (decarburized layer) of the base steel plate are thinner, they are effective as collection sites for hydrogen. Therefore, the average diameter of the oxide grain is adjusted to 500 nm or less. In order to more effectively suppress hydrogen diffusion, the average grain diameter of the oxides is preferably adjusted to 300 nm or less and more preferably adjusted to 100 nm or less. Although the lower limit of the average grain diameter of the oxides is not particularly adjusted, for the adjustment of the average grain diameter to less than 30 nm, it is necessary to strictly control the treatment atmospheres and temperatures in the steel plate manufacturing processes basis, which becomes difficult in practical application. In this way, the average grain diameter of the oxides is preferably adjusted to 30 nm or more.
[00160] Incidentally, the oxides in the superficial part of the layer (decarburized layer) of the base steel plate are observed on a measuring surface obtained by finishing with a mirror.
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46/113 a cross section parallel to the rolling direction of the steel sheet and perpendicular to the surface of the sheet by using an FE-SEM. The density of the oxides is obtained by observing 7 pm ² of the decarburized layer to count the number of oxides or using an observation area necessary for counting up to 1000 oxides. In this case, the observation area means a two-dimensional area of the part to observe the oxides. In addition, the average grain diameter of the oxides is obtained by calculating the average of the diameters equivalent to the circles of 100 to 1000 oxides chosen at random. In this case, the diameter equivalent to the circle means the square root of the product of a larger axis diameter and the secondary axis diameter of a two-dimensional shape of the part to observe the oxides.
[Work hardening coefficient (n value) of the base steel sheet] [00161] As the base steel sheet moldability assessment, it is effective to use a work hardening coefficient (n value) and the value of n the base steel plate in the high-strength hot-dip galvanized steel plate of this modality is desirably 0.060 or more. When the value of n of the base steel sheet is less than 0.060, the moldability of the steel sheet deteriorates to cause a risk of fracture of the steel sheet during difficult molding work.
[Anisotropy index of delayed fracture resistance] [00162] The delayed fracture resistance can be attributed to the fact that hydrogen to enter externally mainly diffuses into the steel plate to cause hydrogen fragility. Therefore, as an anisotropy index of delayed fracture resistance, particularly an anisotropy index in the plane, it is possible to use a ratio of H (RD) / H (TD) that has a value of a limit diffusible hydrogen content H (RD ) in the lamination direction
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47/113 on the surface parallel to the plate surface (laminated surface) of the base steel plate divided by a diffusible hydrogen content H limit (TD) in the direction of the plate width on the surface parallel to the plate surface (laminated surface) of the plate base steel similarly. In the high-strength hot-dip galvanized steel sheet of this modality, the proportion value described before H (RD) / H (TD) of the base steel sheet is desirably in the range of 0.5 to 2.0 range and more desirably in the 0.5 to 1.5. When the value of the proportion described above H (RD) / H (TD) is less than 0.5 or exceeds 2.0, the anisotropy in the plane of the delayed fracture resistance in the steel plate is large and to ensure safety when the steel sheet is used as a part to which a large load will be applied, increasing the restriction in terms of design or work.
[00163] Incidentally, the limit hydrogen content that can diffuse in this case means a hydrogen content in the steel plate when hydrogen is forced to enter (be charged) inside the surface of the steel plate and a charge (effort) is applied to the steel sheet and fracture occurs (on the contrary, a limit hydrogen content that does not cause fracture due to hydrogen fragility). Therefore, the limit hydrogen content that can diffuse in the direction of lamination on the surface parallel to the plate surface (laminated surface) of the base steel plate means a limit diffusible hydrogen content when a load is applied to the steel plate in the direction of lamination. The hydrogen content that can diffuse in the direction of the plate width on the surface parallel to the plate surface (laminated surface) of the base steel plate means a limitable diffusible hydrogen content when a load is applied to the steel plate in the width direction the plate.
[00164] As a method of measuring the limit diffusible hydrogen content to assess the anisotropy of delayed fracture resistance, the following method can be applied with reference to Literature without
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Patent 48/113 1. In addition, on steel sheets in the examples to be described later, the diffusible hydrogen contents at the limit in the direction of rolling and in the direction of the width of the sheet of a base steel sheet were measured by the method.
[00165] That is, from the steel plate, specimens were first cut in the direction of the lamination and along the width of the sheet and the specimens are cut preliminarily worked each in a U shape. So, it is 0.6 times the tensile strength is applied to a U-shaped part of each specimen and then the specimens are charged with hydrogen by cathode electrolysis at a current density of 0.05 mA / cm ² in a solution of 0.3% ammonium thiocyanate and a hydrogen content in each of the specimens immediately after the fracture is measured by an analysis with temperature programmed by gas chromatography. The respective hydrogen contents of the specimen in the lamination direction and in the specimen in the direction of the sheet width that are measured in this way are adjusted up to the limit diffusible hydrogen content in the lamination direction and the limit diffusible hydrogen content in the direction of the plate width respectively.
[00166] In addition, as the evaluation of the delayed fracture resistance of the steel sheet itself, the U-shaped specimens in both directions that are prepared in the same way as above are immersed in hydrochloric acid and the case where a or more of the specimens are fractured within 24 hours it is determined that the delayed fracture resistance is weak.
[Hot-dip galvanizing layer] [00167] The high-strength hot-dip galvanized steel sheet of this modality is one in which the hot-dip galvanizing layer is formed over the decarburized layer on the steel sheet
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49/113 base previously described. An adhesion amount of the hot dip galvanizing layer is not particularly limited, however it is desirably 20 g / m ² or more in view of the corrosion resistance of the steel sheet and is desirably 150 g / m ² or less in view of the economic efficiency.
[00168] In addition, this hot dip galvanizing layer can also be an alloy layer composed mainly of a Zn-Fe alloy (hot dip galvanized alloy layer). The composite alloy layer mainly composed of a Zn-Fe alloy (alloy layer by galvanizing a) is formed in such a way that an electroplating layer of Zn is formed on the surface of the base steel plate by hot galvanizing for then be reheated to a temperature equal to or higher than the melting point of Zn and is subjected to an alloying treatment to diffuse Fe in the base steel plate to the electrodeposition layer. In this case, the average Fe content in the alloy layer by hot dip galvanizing is preferably in the range of 8.0 to 12.0% by weight. Furthermore, even when the hot dip galvanizing layer contains one or two or more species of Pb, Sb, Si, Sn, Mg, Mn, Ni, Cr, Co, Ca, Cu, Li, Ti, Be, Bi, Sr, I, Cs and REM in small amounts in addition to Zn and Fe, the effect of the present invention is not impaired. In addition, depending on its quantity, this has the advantage such as improvements in corrosion resistance and moldability.
[00169] In the following, an example of a method of manufacturing a high-strength hot-dip galvanized steel sheet of this modality will be explained.
[Casting a plate] [00170] First, a plate that has chemical components (composition) controlled in relation to the base steel plate previously described in casting according to a common method such as
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50/113 mo a continuous casting or a thin plate melter and the plate is hot rolled. Incidentally, the manufacturing process of high-strength hot-dip galvanized steel sheet in this modality is also compatible with a process such as continuous direct rolling in the casting (CC-DR) in which the hot rolling is carried out immediately after casting .
[Plate heating] [00171] The obtained plate is heated to a temperature of 1080 ° C or higher, preferably 1180 ° C or higher for hot rolling. To suppress the anisotropy of the crystal orientations attributable to the casting, it is necessary to adjust the heating temperature of the plate to 1080 ° C or higher, preferably 1180 ° C or higher. In addition, in view of the above, the heating temperature of the plate is most preferably adjusted to 1200 ° C or higher. The upper limit of the plate heating temperature is not particularly established, however for heating it is higher than 1300 ° C, a large amount of energy needs to be applied, so that the temperature for heating the plate is preferably adjusted up to 1300 ° C or lower.
[Hot rolling] [00172] After heating the plate, hot rolling is performed. When laminating is carried out in hot work, the hardness of the inclusions decreases at high temperature. Therefore, when excessive reduction is carried out at high temperature, the inclusions are extended in one direction, resulting in the fact that the delayed fracture resistance in the steel plate deteriorates and its anisotropy also increases. To avoid this, hot rolling is performed on a strip that meets Expression 1 below. Incidentally, in Expression 1, the N of the hot rolling mill represents the total number of rolling passes. In addition, the Σ content represents an ex
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51/113 pressure to the nth pass in hot rolling, i represents a pass number (i = 1 to N), TP, represents a rolling temperature in the nth pass (° C) and r, represents a reduction ratio in the nth pass (-). As the pass is earlier in terms of time, the value of the pass number i becomes a smaller value.
[Numerical expression 21 □ 10 £ Z1.00xlO ^{, 0} xexp. -r
2.44xl0 ⁴ ] f 1 1 (Γη ₊ 273) f ^X t0M33 ^) ^{1 00x10} • · · (Expression 1) [00173] Expression 1 is an expression to evaluate the extent of inclusions by lamination. Expression 1 expresses that since the value of Expression 1 is less, the inclusions are extended isotropically to be harmless. The exponential term in Expression 1 is a term related to the stress distribution between a part of the iron in the steel plate and inclusions. The term expresses that the value of this term is greater, the effort makes the inclusions enter easily and the inclusions are easily extended in one direction. In Expression 1, the term of {1 / (1543 - TP,) -1.00 χ 10 ^-3 } is a term related to the softness of inclusions. The term expresses that as the value of this term is greater, the inclusions are soft and are easily extended in one direction.
[00174] Thus, in this mode, a reduction amount and a lamination temperature in each pass are controlled in such a way that the value of Expression 1 becomes 1.00 or less. This makes it possible to avoid excessive extension of the inclusions, so that it is possible to sufficiently obtain a good property such as the delayed fracture resistance in the steel plate and to prevent the anisotropy of the delayed fracture resistance from increasing. In order to safely suppress the extension of the inclusions, the value of Expression 1 is preferably adjusted to 0.90 or less and more preferred
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52/113 Velcely adjusted to 0.80 or less.
[00175] On the other hand, when the value of Expression 1 drops to 0.10, excessive lamination is carried out in a low temperature region, resulting in the fact that anisotropy is generated in an austenite texture on the steel plate. When a strong anisotropy is generated in austenite, the strong anisotropy is provided only for a hot rolled spiral obtained after cooling, but also for several structures transformed into the steel sheet obtained after cold rolling and annealing, so that it is Anisotropy of the delayed fracture resistance in the steel plate is generated. In view of this, the value of Expression 1 needs to be adjusted to 0.10 or more. To further reduce the anisotropy of the delayed fracture resistance in the steel sheet, the value of Expression 1 is preferably adjusted to 0.20 or more and more preferably adjusted to 0.30 or more.
[00176] The temperature of the hot finish lamination is adjusted to be in the range of 850 to 980 ° C, preferably in the range of 850 to 950 ° C. When the temperature of the hot-finished rolling mill is less than 850 ° C, a strong anisotropy is generated in the austenite to reinforce the texture of a product plate and the anisotropy of the delayed fracture resistance in the steel plate is improved. On the other hand, when the temperature of the hot finish laminate exceeds 980 ° C, it becomes difficult to limit the value of Expression 1 to 1.00 or less, resulting in the fact that the inclusions are extended in one direction and the anisotropy of the delayed fracture resistance in the steel plate is improved.
[For primary cooling after hot rolling] [00177] After hot rolling is finished, the hot rolled steel sheet is quickly cooled to be wound on a coil. The time until the start of this rapid cooling (primary cooling) and the conditions of rapid cooling (primary cooling)
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53/113 affect the anisotropy of the steel sheet, so it needs to be controlled appropriately. That is, a period of time from the hot finish lamination to the start of cooling is set to 1.0 seconds or longer, the cooling (primary cooling) is carried out at a cooling rate of not less than 5 ° C / s not more than 50 ° C / s and primary cooling is interrupted at a temperature in the range of 500 to 650 ° C. These limiting reasons are as follows.
[00178] That is, immediately after hot rolling, the texture of austenite in the steel plate has strong anisotropy per work. To reduce this anisotropy, it is necessary to promote the recrystallization of austenite between the hot finish lamination and the start of the primary cooling. In view of this, the time from the hot finish lamination to the start of cooling is prescribed to be 1.0 seconds or longer. To further promote the recrystallization of austenite, it is preferably adjusted to 1.5 seconds or longer and more preferably adjusted to 2.0 seconds or longer. The upper time limit is not particularly adjusted, but to start cooling after a longer time than 20 seconds, sufficient space is needed to hold the steel plate there after hot rolling and an increase is required significant in the size of an installation, which is not preferable in terms of costs. Therefore, the time is preferably adjusted up to 20 seconds or shorter in view of the costs, it is also preferably adjusted up to 15 seconds or shorter. [Primary cooling] [00179] After hot rolling is complete, the hot rolled steel sheet is quickly cooled (primarily cooled) to an appropriate temperature as described above to wind the hot rolled steel sheet onto a coil. Concrete
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54/113, the hot-rolled steel sheet is cooled (primarily cooled) at a cooling rate of 50 ° C / s or less (preferably 5 ° C / s or greater) and primary cooling is stopped at a temperature in the range of 500 to 650 ° C.
[00180] When the cooling rate of this primary cooling is excessively large, the anisotropies of various structures transformed into a hot rolled coil become strong, so that an average cooling rate in the primary cooling after the lamination is completed is adjusted until 50 ° C / s or less. In this case, the average cooling rate is a value of the absolute value of a difference between a temperature at the start of a target section, (which is a primary cooling step) and a temperature at the time the section is finished divided by the time needed for the section. As the average cooling rate of the primary cooling is lower, the anisotropies in the hot rolled coil become weaker, so that an average cooling rate is preferably adjusted to 42 ° C / s or less and more preferably adjusted to 35 ° C / s or less. The lower limit of the average cooling rate in primary cooling is not particularly limited, however, in order to sufficiently cool the hot rolled steel sheet to the cooling temperature at a cooling rate of less than 5 ° C / second, it is necessary a huge installation, which is not preferable in terms of costs. Therefore, the average cooling rate of the primary cooling is preferably adjusted to 5 ° C / s or more and more preferably adjusted to 10 ° C / s or more.
[00181] A temperature of interruption of the cooling in the primary cooling affects the transformation of the structure during a step of winding the hot rolled steel sheet in a coil. That is, in the step of winding the hot-rolled steel sheet as a coil (corresponding to secondary cooling), the perimeter
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55/113 lita and / or coarse cementite that has a large diameter greater than 1 pm are / is generated in hot-rolled steel sheet, thus making it possible to choose randomly textures and shapes of the various transformed structures to reduce anisotropies in an annealing step after cold rolling. In order to generate coarse pearlite and / or cementite, the primary cooling interruption temperature after hot rolling is adjusted to 500 ° C or higher. To sufficiently reduce the anisotropy of the steel sheet, the primary cooling interruption temperature is preferably 530 ° C or higher and more preferably 550 ° C or higher. On the other hand, when the primary cooling interruption temperature is raised too much, an encrustation layer on the part of the superficial layer of the steel sheet becomes excessively thick and the surface quality is impaired, so that it is necessary to adjust the temperature of the steel sheet. interruption of primary cooling to 650 ° C or lower. In view of this, the primary cooling interruption temperature is preferably adjusted to 630 ° C or less.
[Secondary Winding / Cooling] [00182] As previously described, in the step of winding the hot-rolled steel sheet cooled primarily as a coil in a continuous fashion, the hot-rolled steel sheet is cooled slowly in such a way that a period the time elapsed from the interruption of the primary cooling to 400 ° C becomes 1 hour or longer (secondary cooling stage). That is, in order to sufficiently generate the pearlite and / or coarse cementite to reduce the anisotropy of the delayed fracture resistance in the steel sheet, the hot-rolled steel sheet needs to be maintained for a sufficient time in a temperature region at that cementite is generated after rapid cooling is stopped in the
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56/113 primary cooling stage. Therefore, the cold-rolled hot-rolled steel sheet is primarily cooled slowly (cooled secondarily) in such a way that the time elapsed from the interruption of the rapid cooling in the primary cooling stage to 400 ° C becomes 1.0 hour or more long. The elapsed time is preferably adjusted to 2.0 hours or longer and more preferably adjusted to 3.0 hours or longer. The upper limit of elapsed time is not particularly established, but a special installation is required to keep the hot rolled steel sheet for a longer time than 24.0 hours, which is not preferable in terms of cost, so that an elapsed time is preferably adjusted to 24.0 hours or less. Incidentally, the secondary cooling described above usually overlaps with the winding step, but of course it is that the elapsed time described above can also include up to a period when the wound coil is left to stand. In addition, of course, slow cooling in the secondary cooling step includes the case where the hot-rolled steel sheet primarily cooled to a specific temperature is maintained for a partial period of time as described above.
[Cold rolling] [00183] On the steel sheet wound as a hot rolled coil as described above, cold rolling is performed thereafter.
[00184] Cold rolling is carried out in such a way that the total reduction ratio becomes not less than 30% nor greater than 75%. Cold rolling is preferably performed on a large number of passes and any number of rolling passes and any reduction ratio distribution for each pass are applicable. When the total proportion of lamination reduction to
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57/113 cold drops below 30%, sufficient effort is not accumulated on the steel plate, in the annealing stage after that, the recrystallization does not progress sufficiently and the structures remain in a worked state. As a result, the anisotropies of textures and grains of ferrite crystal in the steel plate become strong and anisotropy of the delayed fracture resistance occurs in the steel plate. To sufficiently accumulate the stress on the steel sheet, the total reduction ratio of the cold rolling is preferably adjusted to 33% or more and most preferably adjusted to 36% or more. On the other hand, when the total proportion of reduction in cold rolling exceeds 75%, a recrystallized ferrite texture develops and the anisotropy of the delayed fracture resistance in the steel plate occurs. Therefore, the total proportion of cold rolling reduction is preferably adjusted to 75% or less. In view of this, the total reduction ratio of the cold rolling is preferably adjusted to 65% or less and more preferably adjusted to 60% or less.
[Annealing] [00185] Next, on a cold rolled steel plate (from the base steel plate) obtained as before, an annealing process is carried out. In a cooling process after reaching the maximum heating temperature during this annealing step, a hot-dip galvanizing treatment is desirably incorporated on the steel sheet surface (in addition, an alloying treatment of an electroplating layer depending on the circumstances). That is, as an installation for carrying out an annealing step, preferably continuous annealing is used and the electroplating line which has a preheating zone, a reduction zone and an electroplating zone is preferably used. Thus, here below, the case where a continuous treatment whose steps related to electrodeposition are
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58/113 incorporated to the cooling process after annealing is carried out through the use of such continuous annealing and the electrodeposition line will be explained as an example.
[00186] An annealing step is adjusted such that the temperature is increased in such a way that an average increasing rate of temperature in the range of 600 to 750 ° C becomes 20 ° C / s or less and the base steel plate it is heated to a temperature of 750 ° C or higher and is cooled (first cooled) in such a way that the average cooling rate in the range of 750 to 650 ° C becomes 1.0 to 15.0 ° C / second. In this case, the average rate of temperature increase is a value of the absolute value of the difference between a temperature at the start of a target section, (which is the section of the preheat zone, in this case) and a temperature at the time of finishing of the target section divided by the time required for the section. Incidentally, the average cooling rate is as previously described.
[00187] In this case, in the continuous annealing and electrodeposition line, a temperature increase process is carried out first, which includes a temperature increase at an average temperature increase of 20 ° C / s or less in the range of 600 to 750 ° C described above in the preheat zone. In the reduction zone below, the temperature of the base steel plate is raised to the maximum heating temperature (750 ° C or higher) of the annealing. After that, during the cooling process until the electrodeposition zone, as the first cooling, cooling is performed at an average cooling rate of 1.0 to 15.0 ° C / s in the range of 750 to 650 ° C described above.
[00188] These annealing conditions will be explained below.
[00189] The rate of increase in the temperature of the base steel plate in the annealing step affects the behavior of recrystallization in the base steel plate. In particular, the rate of increase in temperature
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59/113 r at 600 to 750 ° C is important and an average rate of increase in temperature during this period is adjusted to 20 ° C / s or less, thereby making it sufficiently possible to promote recrystallization. In this way, it is possible to make the textures, the ferrite crystal grains and the island-shaped structures isotropic and decrease the non-crystallized ferrite to cause the deterioration of the ductility of the base steel plate. In addition, to decrease the non-crystallized ferrite to improve the ductility of the base steel plate, the average rate of temperature rise at 600 to 750 ° C is preferably adjusted to 15 ° C / s or less and more preferably adjusted to 12 ° C / s or less. The lower limit of the average rate of temperature rise is not particularly limited, but when the average rate of temperature rise is adjusted to 0.5 ° C / s or less, the productivity of the base steel plate decreases significantly, so that the average rate of temperature rise is preferably adjusted to 0.5 ° C / s or more.
[00190] In addition, a process of increasing the temperature in the annealing step is carried out in the preheating zone in the continuous annealing and in the electrodeposition line. At least part of the preheating zone is adjusted to an oxidation treatment zone. Then, in the oxidation treatment zone, an oxidation treatment is desirably carried out to form a Fe oxide coating film that has an appropriate thickness on the surface part of the base steel sheet layer. That is, as a pretreatment at the stage when the decarburized layer is formed on the surface part of the steel sheet layer by heating in the following reduction zone, the Fe oxide coating film having an appropriate thickness is desirably formed in the superficial part of the base steel sheet layer in the oxidation treatment zone which is at least part of the preheated zone
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60/113 ment. In this case, the temperature of the steel sheet when it passes in the oxidation treatment zone is adjusted to 400 to 800 ° C and with the proviso that an air proportion (a value of the air contained in a mixed gas per unit volume, a mixed air gas being used for a gas preheating and combustion burner, divided by the volume of air theoretically necessary to cause complete combustion gas combustion contained in the mixed gas per unit volume (= [volume of air contained in a mixed gas per unit volume] + [volume of air theoretically necessary to cause complete combustion gas combustion contained in the mixed gas per unit volume]) is adjusted to 0.7 to 1.2, preheating is performed. Thus, the Fe oxide coating film having a thickness of 0.01 to 20 pm is desirably formed on the surface part of the base steel sheet layer.
[00191] In this case, when the proportion of air described above in the oxidation treatment zone exceeds 1.2, there is a risk that the oxide coating film will grow excessively and the decarburized layer will grow excessively in the next reduction zone. In addition, there is a risk that in the reduction zone, the oxide coating film cannot be reduced completely to remain on the surface part of a steel sheet layer and the slab production capacity decreases. On the other hand, when the air ratio described above is less than 0.7, an oxide coating film is not formed sufficiently in the surface part of the base steel sheet layer. In this case, the oxide coating film to be formed on the superficial part of the base steel sheet layer in the oxidation treatment zone of the preheating zone works as a source of oxygen supply containing Si and / or Mn in the decarburized layer. to be formed in the reduction zone below. In this way, unless the coating film
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61/113 oxide is sufficiently formed on the surface part of the base steel sheet layer, there is a risk that a decarburized layer already described in which the oxides are highly densely dispersed cannot be obtained.
[00192] In addition, when the temperature of the steel sheet when it passes through the oxidation treatment zone of the preheating zone is less than 400 ° C, a sufficient oxide coating film cannot be formed on the surface of the base steel sheet layer. On the other hand, when the temperature of the base steel plate when it passes through the oxidation treatment zone of the preheating zone is at a high temperature greater than 800 ° C, the oxide coating film grows excessively on the surface part of the layer of the base steel sheet, so that it becomes difficult to make the thickness of the decarburized layer remain within a predetermined range.
[00193] The maximum heating temperature of the base steel plate in the annealing step is adjusted up to 750 ° C or higher and a reason for this is as follows.
[00194] That is, when the maximum heating temperature of the base steel plate in the annealing step is low, the coarse cementite is left without melting and the ductility of the base steel plate deteriorates significantly. To sufficiently guarantee the ductility of the base steel sheet, the maximum heating temperature of the base steel sheet is set up to 750 ° C or higher and preferably set up to 760 ° C or higher. The upper limit of the maximum heating temperature of the base steel plate is not particularly adjusted, but when the base steel plate is heated beyond 1000 ° C, the surface quality of the steel plate is significantly impaired and the wettability of the electrodeposition is reduced. deteriorates. Therefore, the maximum heating temperature of the
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62/113 base steel is preferably adjusted to 1000 ° C or less and more preferably adjusted to 950 ° C or less.
[00195] In addition, in the zone of reduction in continuous annealing and in the electrodeposition line, the temperature of the base steel plate in the annealing step is desirably high up to the maximum heating temperature. In the reduction zone, it is possible to reduce the Fe oxide coating film formed in the treatment zone by oxidizing the preheating zone to form the decarburized layer and to transform the decarburized layer (surface layer) into a structure in which the oxides containing Si and / or Mn are moderately dispersed. An atmosphere of the reduction zone is desirably adjusted to an atmosphere in which a value of a partial pressure ratio P (H2O) / P (H2) which is a value of a partial pressure of water vapor P (H2O) divided by a partial pressure of hydrogen P (H2) is in the range of 0.0001 to 2.00. When the proportion of partial pressure described above P (H2O) / P (H2) is less than 0.0001, oxides containing Si and / or Mn are formed only in the upper layer of the base steel plate surface, to thereby make it difficult to disperse moderately the oxides containing Si and / or Mn within the decarburized layer. On the other hand, when the proportion of partial pressure described above P (H2O) / P (H2) exceeds 2.00, decarburization progresses excessively until there is a risk that the thickness of the decarburized layer cannot be controlled to be in a predetermined range . Incidentally, the partial pressure ratio described above P (H2O) / P (H2) is preferably adjusted to be in the range of 0.001 to 1.50 range and most preferably adjusted to be in the range of 0.002 to 1.20.
[00196] The process of cooling a maximum heating temperature of the base steel plate in the annealing step is im
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63/113 carrier to generate sufficient ferrite in the base steel plate. In this way, the base steel sheet needs to be cooled in such a way that the average cooling rate of cooling in the range of 750 to 650 ° C in this cooling process (a first cooling step) becomes 1.0 to 15.0 ° C / s. That is, the range of 750 ° C to 650 ° C is a temperature region in which the ferrite is generated in the base steel plate. In this way, the average cooling rate of the first cooling in the temperature region is adjusted to not less than 1.0 ° C / s or more than 15 ° C / s, thereby making it possible to generate a sufficient amount of ferrite in the base steel plate. When the average cooling rate of the first cooling exceeds 15 ° C / s, sometimes a sufficient amount of ferrite cannot be obtained and the ductility of the base steel plate deteriorates. On the other hand, when the average cooling rate of the first cooling falls below 1.0 ° C / s, in the base steel plate, the ferrite is generated excessively, it is generated perlite and the like, resulting in the fact that it cannot be a sufficient amount of hard structure is obtained. As a result, the strength of the base steel plate deteriorates.
[00197] In addition, an average rate of cooling (a second cooling step) until the temperature of the base steel plate becomes the temperature for interrupting cooling to enter a 650 ° C electrodeposition bath in the process cooling of the annealing step is preferably adjusted to 3.0 ° C / s or more. This is to obtain hard structures in which the orientations of the crystal are more random, further decreasing the transformation temperature in the hard structure. In view of this, the average cooling rate of the second cooling is most preferably adjusted to 5.0 ° C / s or more. The upper limit of the average cooling rate of the second cooling is not particularly adjusted, however, to adjust the average cooling rate to 200 ° C / s or more, it is necessary to
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64/113 would require a special cooling installation, so that the average cooling rate is preferably adjusted to 200 ° C / s or less.
[00198] In this modality, by coarse lamination · the finishing lamination being the lamination after heating in the hot rolling stage, which provides effort and a temperature history for the steel plate in the cooling stage and in the winding stage and which provides effort and a temperature history for the steel plate in the next cold rolling stage and in the annealing stage, the textures are made isotopic. As a result, the speeds of recrystallization and crystal growth are also made isotropic and a proportion, of the ferrite and the hard structure, the diameter of the grain in the direction of lamination and the diameter of the grain in the direction of the width of the plate (d ( RD) / d (TD)) becomes 0.75 to 1.33. [Hot dip galvanizing] [00152] Subsequently, the base steel sheet is immersed in the hot dip galvanizing bath in the electrodeposition zone to be subjected to hot dip galvanizing. The electrodeposition bath is composed mainly of zinc. In addition, an effective amount of Al which is a value obtained by subtracting the total amount of Fe from the total amount of Al in the electrodeposition bath is preferably adjusted to be in the range of 0.01 to 0.18% by weight. Particularly, when the alloy formation treatment is carried out after electrodeposition, the effective amount of Al in the electrodeposition bath is preferably adjusted to be in the range of 0.07 to 0.12 mass% to control the formation progress of alloy of the electrodeposition layer.
[00153] Furthermore, when the electrodeposition layer is not alloyed, no problem is caused even if the effective amount of Al in the electrodeposition bath is in the range of 0.18 to
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65/113
0.30% by mass.
[00154] Furthermore, even when one species or two or more species of Pb, Sb, Si, Sn, Mg, Mn, Ni, Cr, Co, Ca, Cu, Li, Ti, Be, Bi, Sr, I, Cs, REM are mixed in the galvanizing bath, the effect of the present invention is not impaired. Depending on its quantity, this has advantages such as improvements in corrosion resistance and moldability.
[00156] The temperature of the electrodeposition bath is preferably adjusted to 450 ° C to 470 ° C. When the temperature of the electrodeposition bath is less than 450 ° C, the viscosity of the electrodeposition bath becomes excessively high, the control of the thickness of the electrodeposition layer becomes difficult and the external appearance of the steel plate is impaired. On the other hand, when the temperature of the electrodeposition bath exceeds 470 ° C, a lot of smoke arises and safe manufacturing becomes difficult, so that the temperature of the electrodeposition bath is preferably 470 ° C or lower. In addition, when the temperature of the steel plate when the steel plate enters the electrodeposition bath drops below 430 ° C, there is a need to provide a large amount of heat to the electrodeposition bath to stabilize the temperature of the electrodeposition bath. electroplating at 450 ° C or higher, which is not preferable for practical use. On the other hand, when the temperature of the steel plate when the steel plate enters the electrodeposition bath exceeds 490 ° C, an installation needs to be introduced in which a large amount of heat is removed from the electrodeposition bath to stabilize the bath temperature electrodeposition at 470 ° C or lower, which is not preferable in terms of cost. Thus, in order to stabilize the temperature of the electrodeposition bath, the temperature at which the steel sheet enters the electrodeposition bath is preferably adjusted to 430 ° C to 490 ° C.
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66/113 [Bainital transformation process [00157] In addition, before or after immersion in the electrodeposition bath, a process in which the steel sheet is kept for 20 to 1000 seconds at a temperature in the range of 300 to 470 ° C (bainite transformation process) can be carried out with the purpose of promoting the transformation of bainite to improve the strength, ductility and the like of the steel sheet. In addition, the alloy formation treatment is carried out after electrodeposition, the bainite transformation process can also be carried out before or after the alloy formation treatment.
[00158] However, the bainite transformation process affects the final proportion of austenite retained in the base steel plate. On the other hand, in this modality, the amount of austenite retained in the base steel plate is controlled to be small. Thus, the time period for carrying out the bainite transformation process is desirably selected in an appropriate manner in consideration of the effect of the bainite process on the amount of austenite retained.
[00159] That is, when the bainite transformation process is carried out at a temperature of 430 ° C or lower (300 ° C or higher), there is sometimes a case that with the progress of the transformation of bainite, a large amount of carbon is concentrated to untransformed austenite and when it cools to room temperature thereafter, the volume fraction of retained austenite that remains base steel plate increases. On the other hand, the amount of carbon in the solid solution in austenite is decreased by reheating the base steel plate to a temperature higher than the temperature that causes the transformation of the bainite. Then, as long as the bainite transformation process is carried out at the stage before the base steel sheet that is immersed in the electrodeposition bath, the steel sheet is reheated to the temperature of the electrodeposition bath in the
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67/113 after immersion in the electrodeposition bath thereafter and in this way the amount of carbon in the solid solution in the untransformed austenite can be decreased and cooled to room temperature after that, the amount of austenite retained that remains in the steel plate base can be decreased. From such a point of view, the bainite transformation process is preferably carried out before the base steel sheet is immersed in the electrodeposition bath. In this case, as long as the temperature of the bainite transformation process is in the range of 300 to 470 ° C, the temperature is not limited to a region of temperature higher than 430 ° C.
[00160] On the other hand, when the bainite transformation process is carried out after immersion in the electrodeposition bath, the bainite transformation process is appropriately carried out in a region with a temperature higher than 430 ° C up to 470 ° C or less to prevent the retained austenite from increasing excessively.
[00161] Incidentally, the temperature of the bainite transformation process (300 to 470 ° C) is often lower than the temperature at which the base steel plate enters the electrodeposition bath (normally, 430 to 490 ° C). Then, when the bainite transformation process is carried out at the stage before the base steel plate is immersed in the electrodeposition bath, subsequently until the bainite transformation process, the base steel plate is desirably reheated and then brought to the electroplating bath.
[Alloy formation treatment of the electrodeposition layer] [00162] After immersion in the electrodeposition bath, the alloy formation treatment of the electrodeposition layer can also be performed. When a temperature for the treatment of alloy formation is less than 470 ° C, the alloy formation of the electrodeposition layer does not progress sufficiently. Therefore, the time
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68/113 rature for the treatment of alloy formation is preferably adjusted up to 470 ° C or higher. In addition, when the temperature for the treatment of alloy formation exceeds 620 ° C, coarse cementite is generated and the strength of a steel plate decreases significantly. Therefore, the temperature for the treatment of alloy formation is preferably adjusted to 620 ° C or lower. From such a point of view, the temperature for the treatment of alloy formation is most preferably set to 480 to 600 ° C and even more preferably set to 490 to 580 ° C.
[00163] An alloying treatment time is preferably adjusted two seconds or longer and more preferably five seconds or longer to achieve sufficiently alloying progress of the electrodeposition layer. On the other hand, when the alloy formation treatment time exceeds 200 seconds, the electrodeposition layer is excessively mixed with alloy to cause a concern that its property deteriorates, so an alloy formation treatment is preferably set up to 200 seconds or less and more preferably set up to 100 seconds or less.
[00164] Incidentally, the alloy formation treatment is preferably carried out after the base steel sheet is immersed in the electrodeposition bath, however it is also possible that after the base steel sheet is immersed, the temperature of the base steel sheet decreased once to 150 ° C or less and before the base steel plate is reheated to the alloy formation treatment temperature.
[Cooling after electroplating (Third cooling step)] [00165] In a cooling process after hot dip galvanizing (after alloying treatment when alloying treatment is carried out immediately after galvanizing
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69/113 hot heat), when an average cooling rate of the steel plate in a cooling step when cooling to a temperature region of 150 ° C or below (a third cooling step) then drops 0.5 ° C / second, coarse cementite is generated to cause concern that the strength and / or ductility of the steel sheet will deteriorate. Therefore, the average cooling rate of the steel sheet in the third cooling step is preferably adjusted to 0.5 ° C / s or more and more preferably adjusted to 1.0 ° C / s or more.
[00166] In addition, during or after cooling in the third cooling stage after hot dip galvanizing (after alloying treatment when alloying treatment is carried out immediately after hot galvanizing), it can also be carried out a reheat treatment with the aim of tempering the martensite. The heating temperature when the reheat is preferably adjusted to 200 ° C or higher because when it is less than 200 ° C, the quench does not progress sufficiently. In addition, when the heating temperature exceeds 620 ° C, the strength of a steel sheet deteriorates significantly, so that a heating temperature is preferably set to 620 ° C or less and more preferably set to 550 ° C or less .
[00167] In addition, on hot-dip galvanized steel sheet cooled to room temperature, cold rolling at a reduction rate of 3.00% or less (corrective rolling) can also be performed to correct its Format.
[00168] In addition, on the high-strength hot-dip galvanized steel sheet obtained by the method described above, a phosphoric acid-based film forming process can also be performed to form a coating film made of phosphorus oxides and / or composite oxides containing phosphorus. The coating film made of phosphorus oxides and / or composite oxides containing phosphorus
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70/113 can work as a lubricant when the high-strength hot-dip galvanized steel sheet is worked and can protect the electrodeposition layer formed on the surface of the base steel sheet.
[00169] According to this modality explained above, as a hot-dip galvanized steel sheet using a high-strength steel sheet as a base material, it is possible to obtain the high-strength hot-dip galvanized steel sheet that has excellent strength delayed fracture and has small anisotropy of delayed fracture resistance (particularly, anisotropy of delayed fracture resistance on a surface parallel to the plate surface (laminated surface) (anisotropy in the plane)) despite being a thin plate without conferring ductility and strength . In this way, even when the high-strength hot-dip galvanized steel sheet is used as a part on which a high load acts as a thin sheet, high security can be guaranteed and there is a small risk that the galvanized steel sheet will high-strength hot steel is subject to design and work restrictions and in this way it is possible to increase the degree of freedom of the design and work to expand a range of application of a high-strength hot-dip galvanized steel sheet.
[00170] It should be noted that the modality described above simply illustrates a concrete example of implementation of the present invention and the technical scope of the present invention need not be considered in a restrictive manner by the modality. That is, the present invention can be implemented in various ways without leaving the technical spirit or the main aspects of it.
Example [00171] Hereinafter, the present invention will be explained concretely by examples. Incidentally, the following examples serve to illustrate the concrete effects of the present invention and it is to be expected that the conditions described in the examples do not limit the scope
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71/113 technician of the present invention.
[00172] The plates that have the chemical components A to Z, AA to AG presented in Table 1 and Table 2 are cast according to the ordinary method. Immediately after casting, under each condition presented in Experimental Examples 1 to 123 in Table 3 up to Table 7, in the plates, heating is carried out, hot rolling in this order and cooling (primary cooling and secondary cooling) is carried out and the plates hot rolled steel are each wound in a coil. Thereafter, the hot-rolled steel sheets are each subjected to cold rolling to be finished with a cold-rolled steel sheet having a 1.4 mm thick sheet.
[00173] The cold-rolled steel sheets obtained in Experimental Examples 1 to 128 were each annealed under each condition presented in Table 8 to Table 12 (heated to the maximum heating temperature to then be cooled by first cooling and second cooling ) and were subsequently subjected to hot dip galvanizing and then were cooled to a temperature of 150 ° C or lower as a third cooling using a continuous annealing and electroplating line. Incidentally, as the continuous annealing and an electroplating line, one was used that has a preheating zone, a reduction zone and an electroplating zone (oven for hot galvanizing).
[00174] In addition, in some examples (GA-type steel) of Experimental Examples 1 to 128, an alloying furnace was arranged on the downstream side of the furnace for hot dip galvanizing in continuous annealing and in the electroplating line and a treatment for alloy formation of an electrodeposition layer was carried out after hot galvanizing. In relation to other types of steel
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72/113 (GI type steel), no treatment was carried out to form an alloy for an electrodeposition layer, it was carried out after hot galvanizing or a treatment temperature for forming the alloy was adjusted to less than 470 ° C and hot-dip galvanized steel sheets (GI) were manufactured, each having an electroplating layer without alloy.
[00175] In addition, in some examples of Experimental Examples 1 to 128, subsequently until the second cooling in an annealing step, a bainite transformation process (a retention process at 300 to 470 ° C) was carried out and then the base steel plates were each placed in the electrodeposition oven in the electrodeposition zone. However, in Experimental Example 60 of the examples in which the bainite transformation process was carried out, the bainite transformation process was carried out after hot galvanizing. Incidentally, in each of the examples in which the bainite transformation process was carried out and then the base steel plate was taken to an electrodeposition bath, subsequent to the bainite transformation process (retention process), the base steel plate was slightly reheated and then taken to the electrodeposition bath.
[00176] In addition, in some examples of Experimental Examples 1 to 128, after electroplating (after the treatment for alloy formation in case the treatment for alloy formation is being carried out), as a third cooling, the galvanized steel sheets hot (including hot-dip galvanized alloy steel sheets) were each cooled to a temperature of 150 ° C or lower to then be subjected to a hardening step.
[00177] Similarly, in some examples from Experimental Examples 1 to 128, after electrodeposition (after treatment to form an alloy in case the treatment is being carried out
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73/113 for alloy formation), as a third cooling, the hot-dip galvanized steel sheets (including hot-dip galvanized alloy steel sheets) were each cooled to a temperature of 150 ° C or lower and then on the corrected hot-dip galvanized steel (including hot-dip galvanized alloy steel sheets), corrective lamination was performed in cold work.
[00178] In the observation of each of the hot-dip galvanized steel sheets obtained (including the hot-dip galvanized steel sheets with alloy) of Experimental Examples 1 to 128, the microstructure of the base steel sheet (a fraction in each phase, a fraction of non-crystallized ferrite up to the ferrite phase, a ratio of a grain diameter in the direction of the rolling mill / a grain diameter in the direction of the width of the ferrite sheet d (RD) / d (TD), a ratio of one length in the direction of the lamination / a length in the direction of the plate width of a hard structure in the shape of an L (RD) / L (TD) island and a proportion of random X-ray intensity of iron BCC), a thickness of one surface layer (decarburized layer) of the base steel plate and the density and size (an average grain diameter) of oxides in the surface layer (decarburized layer) of the base steel plate were measured by the methods already described. These results are shown in Table 13 through Table 21.
[00179] In addition, considering each of the hot-dip galvanized steel sheets of Experimental Examples 1 to 128, as their performance evaluation, an inspection of the external appearance, a tensile test and a peeling test of the electrodeposition and also as the evaluation of the delayed fracture resistance, a salt spray test was carried out and as the anisotropy evaluation of the delayed fracture resistance, a proportion of a limit diffusible hydrogen content in the lamination direction and a hydrogen content
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74/113 diffusible limit in the direction of the plate width were examined. These results are shown in Table 13 through Table 21.
[00180] Incidentally, the methods of the respective assessment tests are as follows.
[External Appearance Inspection] [00181] On hot-dip galvanized steel sheets (including hot-dip galvanized alloy steel sheets) manufactured by the procedures described above, each inspection of the external appearance was carried out. On this occasion, considering the external appearance of the steel sheet surface, a state of occurrence of electrodeposition was determined by visual observation and the results were presented in Tables 13 to 21 as O and X. Incidentally, each X presented in Tables 13 a 21 indicates the steel plate on which an electrodeposition with a diameter of 0.5 mm or more has been observed and which has deviated from a tolerance range of the external appearance and each O indicates the steel plate which has an external appearance practically permissible without the one above. [Electroplating peeling test] [00182] On each of the steel sheets manufactured by the procedures described above, according to the literature descriptive report other than patent 2, an electroplating peeling test was carried out to assess the capacity of adhesion at the time of work to add compression stress to the steel plate. Concretely, using each of the steel plates, according to a Bending Test of Metallic Materials described in JIS Z 2248, a bending test in V at 60 ° was performed and a specimen was manufactured and then applied a cellophane tape to an inner side of the folded part of the specimen and the cellophane tape was removed. Then, from a peeled state of the peeling electrodeposition layer with cellophane tape, the ca
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75/113 electrodeposition adhesion pacity and the results were presented in Table 13 up to Table 21 as O and X. In this case, each X presented in Tables 13 to 21 indicates a virtually non-permissible steel plate whose peeled width was 7 , 0 mm or more. Each Oindica sheet steel that has electrodeposition adhesives practically permissible other than those above. [Tensile property] [00183] Each of the steel sheets of the Experimental Examples was worked on to obtain N ° specimen. 5 described in JIS Z 2201. Considering the specimens obtained, according to a test method described in JIS Z 2241, tensile strength (MPa) and total elongation (%) were measured and also according to a test method described in JIS G 0202, the yield strength (MPa) was also measured. In addition, as for a value of n (work hardening coefficient), the tensile test results showed that nominal efforts were made at a nominal stress point of 3% and a nominal stress point of 7% and the efforts Nominal and nominal deformations were converted into true stresses of σ3% and σ7% and true deformations of ε3% and ε7% and the value of n (hardening coefficient by work) was obtained according to the following expression.
{n = Ιθ9 (σ7% / σ3%) / 1θ9 (ε7% / ε3%)} [00184] However, considering the steel plate with uniform elongation less than 7%, the value of n (coefficient hardening by work) was obtained according to the expression described above two points: the point of nominal deformation of 3% and the point of maximum tractive effort.
[00185] Additionally, the delayed fracture resistance and anisotropy of the fracture were measured and evaluated by the methods already described.
Petition 870190028455, of March 25, 2019, p. 84/134 [Table 1]
Chemical Component Chemical Composition (% by mass) Ç Si Mn P s THERE N 0 You Nb V Cr THE 0 142 0.53 2.35 0.0055 0.0032 0.048 0.0021 0.0007 B 0.220 0.35 1.77 0.0065 0.0013 0.257 0.0030 0.0005 Ç 0.102 1.72 1.26 0.0125 0.0008 0.043 0.0042 0.0010 D 0.357 0.05 2.50 0.0086 0.0037 0.725 0.0025 0.0011 AND 0.081 1.16 2.83 0.0111 0.0044 0.020 0.0019 0.0003 F 0.237 1.53 1.94 00093 0.0016 0.045 0.0038 0.0025 G 0.255 1.79 2.01 0.0078 0.0014 0.053 0.0052 0.00100.015 H 0.093 0.87 2.00 0.0143 0.0041 0.066 0.0038 0.0007 0.039 I 0.113 1.09 1.17 0.0135 0.0059 0.069 0.0033 0.0014 J 0.212 0.68 1.41 0.0195 0.0046 0.070 0.0039 0.0032 0.112K 0.161 0.42 1.55 0.0125 0.0050 0.064 0.0028 0.0004 L 0.240 0.73 1.52 0.0129 0.0009 0.056 0.0059 0.0003 M 0.171 1.14 1.15 0.0079 0.0025 0.090 0.0018 0.0013 0.30 N 0.156 0.63 2.72 0.0159 0.0022 0.034 0.0023 0.0022 O 0.130 1.38 2.50 0.0063 0.0057 0.051 0.0027 0.0022 P 0.263 0.74 1.67 0.0071 0.0023 0.057 0.0024 0.0007 Q 0.093 1.86 1.78 0.0060 0.0028 0.022 0.0048 0.0021 R 0.150 0.18 1.29 0.0159 0.0007 1,158 0.0038 0.0022 0.004 0.008 s 0.195 0.27 2.72 0.0105 0.0037 0.047 0.0027 0.0016 0.081
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Petition 870190028455, of March 25, 2019, p. 85/134 [Table 1] -continuation-
Chemical Component Chemical Composition (% by mass) Classification Ni Ass Mo B W Here Ce Mg Zr There REM Faith THE REMAINING EXAMPLE B REMAINING EXAMPLE Ç REMAINING EXAMPLE D REMAINING EXAMPLE AND REMAINING EXAMPLE F 0.52 0.57 0.0012 REMAINING EXAMPLE G REMAINING EXAMPLE H 0.00080.0009REMAINING EXAMPLE I 1.13 REMAINING EXAMPLE J REMAINING EXAMPLE K 0.0035 REMAINING EXAMPLE L0.19REMAINING EXAMPLE M 0.05 REMAINING EXAMPLE N0.0014 0.0026 REMAINING EXAMPLE O 0.2500 REMAINING EXAMPLE P 0.0052 REMAINING EXAMPLE Q 0.0028 REMAINING EXAMPLE R 0.0051 0.0009 REMAINING EXAMPLE s REMAINING EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 86/134 [Table 2]
CHEMICAL COMPOSITION Component (% IN MASS)
Chemical Ç Si Mn P s Al N O You Nb V Cr T 0.209 0.70 2.26 0.0067 0.0037 0.015 0.0033 0.0008 0.65 U 0.112 0.52 1.01 0.0135 0.0014 0.221 0.0050 0.0010 V 0.134 0.93 0.84 0.0164 0.0007 0.062 0.0023 0.0015 1.48 W 0.174 1.09 2.45 0.0095 0.0036 0.040 0.0040 0.0033 X 0.192 0.85 1.37 0.0162 0.0061 0.062 0.0020 0.0022 0.021 0.041 Y 0.218 1.42 1.82 0.0202 0.0051 0.028 0.0027 0.0013 Z 0.137 0.99 2.18 0.0143 0.0040 0.072 0.0016 0.0023 AA 0.177 1.65 1.59 0.0087 0.0030 0.016 0.0043 0.0019 AB 0.166 0.57 0.94 0.0046 0.0014 0.346 0.0004 0.0025 B.C 0.209 0.68 1.91 0.0226 0.0027 0.056 0.0025 0.0004 AD 0.277 1.33 2.26 0.0142 0.0053 0.044 0.0043 0.0024 AE 0.062 0.86 2.14 0.0088 0.0046 0.045 0.0036 0.0012 AF 0.490 0.81 2.17 0.0107 0.0046 0.051 0.0038 0.0009 AG 0.147 0.89 0.06 0.0083 0.0045 0.043 0.0045 0.0021 BA 0.164 2.41 2.30 0.015 0.0043 0.108 0.0033 0.0009 BB 0.161 0.00 2.55 0.016 0.0040 0.089 0.0048 0.0016 BC 0.174 0.89 3.96 0.018 0.0028 0.120 0.0033 0.0017 BD 0.172 0.78 2.42 0.008 0.0024 2.38 0.0025 0.0014 BE 0.109 1.77 2.65 0.002 0.0010 0.059 0.0040 0.0008
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Petition 870190028455, of March 25, 2019, p. 87/134 [Table 2] -continuation-
Chemical Component CHEMICAL COMPOSITION (% IN PASTA) CLASSIFICATION Ni Ass Mo B W Here Ce Mg Zr There REM Faith T REMAINING EXAMPLE U 0.16 0.0019 REMAINING EXAMPLE V REMAINING EXAMPLE W0.0019REMAINING EXAMPLE X REMAINING EXAMPLE Y 0.0029 REMAINING EXAMPLE Z0.0034REMAINING EXAMPLE AA 0.0036 REMAINING EXAMPLE AB 0.37 REMAINING EXAMPLE B.C 0.20 0.12 0.0035 REMAINING EXAMPLE AD 0.0018 REMAINING EXAMPLE AE REMAINING COMPARATIVE EXAMPLE AF REMAINING COMPARATIVE EXAMPLE AG REMAINING COMPARATIVE EXAMPLE BA REMAINING COMPARATIVE EXAMPLE BB REMAINING COMPARATIVE EXAMPLE BC REMAINING COMPARATIVE EXAMPLE BD REMAINING COMPARATIVE EXAMPLE BE REMAINING COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 88/134 [Table 3]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP STEP OFCOLD LAMINATION CLASSIFICATION PLATE HEATING TEMPERATURE EXPRESSION 1 TEMPERATURE TO COMPLETE LAMINATION PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RE-TIMEATTENTION UNTIL THE COOLING BEGINS AVERAGE COOLING RATE COOLING END TEMPERATURE TIME TRAVELED UP TO 400 ^O C ° C ° c SECOND ° C / SECOND ° C TIME % 1 THE 1255 0.72 943 3.5 42 595 3.0 40 EXAMPLE 2 THE 1270 0.67 916 2.0 31 631 3.0 52 EXAMPLE 3 THE 1265 0.48 902 5.0 40 561 4.2 50 EXAMPLE 4 THE 1215 2.05 932 4.7 28 556 2.3 65 COMPARATIVE EXAMPLE 5 B 1280 0.50 910 2.0 19 552 2.0 64 EXAMPLE 6 B 1260 0.14 962 3.1 32 589 2.9 50 EXAMPLE 7 B 1190 0.77 965 1.5 33 594 5.4 50 EXAMPLE 8 B 1240 0.46 925 3.6 32 615 3.9 60 COMPARATIVE EXAMPLE 9 Ç 1255 0.83 938 3.5 32 581 2.7 40 EXAMPLE 10 Ç 1205 0.25 918 4.0 28 578 4.9 34 EXAMPLE 11 Ç 1260 0.42 904 3.1 25 543 2.6 55 EXAMPLE 12 Ç 1250 0.38 966 3.1 35 615 3.8 50 COMPARATIVE EXAMPLE 13 D 1280 0.71 913 6.2 37 603 4.5 57 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 89/134
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP STEP OFCOLD LAMINATION CLASSIFICATION PLATE HEATING TEMPERATURE EXPRESSION 1 TEMPERATURE TO COMPLETE LAMINATION PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RE-TIMEATTENTION UNTIL THE COOLING BEGINS AVERAGE COOLING RATE COOLING END TEMPERATURE TIME TRAVELED UP TO 400 ^O C ° C ° c SECOND ° C / SECOND ° C TIME % 14 D 1275 0.73 920 2.3 33 608 1.4 62 EXAMPLE 15 D 1255 0.37 905 1.9 24 570 3.5 45 EXAMPLE 16 D 1240 0.57 922 5.2 28 571 2.6 45 COMPARATIVE EXAMPLE 17 AND 1220 0.46 899 3.9 41 553 2.6 50 EXAMPLE 18 AND 1200 0.35 976 2.3 33 616 7.6 47 EXAMPLE 19 AND 1215 0.19 903 6.8 34 574 5.0 65 EXAMPLE 20 AND 1230 0.48 918 5.1 20 618 5.3 47 COMPARATIVE EXAMPLE 21 F 1220 0.61 940 4.2 38 556 4.3 50 EXAMPLE 22 F 1270 0.33 928 2.4 32 523 2.0 50 EXAMPLE 23 F 1260 0.61 929 1.8 25 596 4.9 32 EXAMPLE 24 F 1250 0.40 966 6.7 86 586 2.8 66 COMPARATIVE EXAMPLE 25 Q 1265 0.78 974 6.6 24 582 4.7 61 EXAMPLE 26 G 1210 0.75 947 2.6 29 597 5.3 37 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 90/134 [Table 4]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP LAMI STEP-COLD NATION O<Oω% O TEMPERATUREHEATINGBOARD EXPRESSION 1 TEMPERATURE TO COMPLETE THE 1 AMINATION PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RETENTION TIME UNTIL THE COOLING BEGINS AVERAGE COOLING RATE TEMPERATU-END OF COOLING RA TIME TRAVELED UP TO 400 ° C ° C ° C SECOND ° C / SECOND ° C TIME % 27 G 1240 0.27 936 4.6 30 611 3.2 58 EXAMPLE 28 G 1260 0.55 978 4.9 36 619 5.6 52 COMPARATIVE EXAMPLE 29 H 1270 0.79 964 6.1 26 582 2.8 40 EXAMPLE 30 H 1265 0.22 943 4.4 28 628 8.3 57 EXAMPLE 31 H 1205 0.46 921 5.5 29 602 6.3 39 EXAMPLE 32 H 1200 0.64 958 2.4 27 554 4.1 66 COMPARATIVE EXAMPLE 33 I 1260 0.77 963 3.3 38 551 4.1 62 EXAMPLE 34 I 1185 0.46 889 4.3 37 572 2.4 39 EXAMPLE 35 I 1205 0.54 960 3.5 27 562 4.5 46 EXAMPLE 36 I 1210 0.61 966 3.1 39 553 05 41 COMPARATIVE EXAMPLE 37 J 1275 0.45 945 4.0 33 644 3.1 57 EXAMPLE 38 J 1270 0.39 927 4.9 31 581 2.6 57 EXAMPLE 39 J 1245 0.46 922 3.0 21 577 2.7 61 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 91/134
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP LAMI STEP-COLD NATION CLASSIFICATION TEMPERATUREHEATINGBOARD EXPRESSION 1 TEMPERATURE TO COMPLETE THE 1 AMINATION PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RETENTION TIME UNTIL THE COOLING BEGINS AVERAGE COOLING RATE COOLING END TEMPERATURE TRANSPORT TIMERUN UNTIL400 ° C ° C ° C SECOND ° C / SECOND ° C TIME % 40 J 1275 0.69 934 2.1 16 736 8.8 39 COMPARATIVE EXAMPLE 41 K 1270 0.35 919 1.9 16 610 3.8 44 EXAMPLE 42 K 1280 0.94 954 6.6 44 572 4.7 42 EXAMPLE 43 K 1230 0.43 945 2.5 26 556 2.3 50 EXAMPLE 44 K 1200 0.48 927 3.3 23 555 2.4 60 COMPARATIVE EXAMPLE 45 L 1255 0.36 895 3.3 14 620 5.6 62 EXAMPLE 46 L 1200 0.28 943 3.3 23 617 1.8 59 EXAMPLE 47 L 1195 0.32 918 7.3 26 590 6.1 64 EXAMPLE 48 L 1200 0.73 943 2.7 32 588 2.6 20 COMPARATIVE EXAMPLE 49 M 1220 0.43 938 2.6 33 612 7.1 47 EXAMPLE 50 M 1235 0.70 888 2.3 24 600 5.3 41 EXAMPLE 51 M 1270 0.81 965 3.1 22 613 5.1 68 EXAMPLE 52 M 1225 0.43 967 6.1 28 576 3.0 37 COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 92/134 [Table 5]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP COLD LAMINATION STAGE CLASSIFICATION PLATE HEATING TEMPERATURE EXPRESSION 1 TEMPERATURE FORCOMPLETE THE BLADE-DOG PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RETENTION TIME UNTIL THE COOLING BEGINS AVERAGE COOLING RATE COOLING END TEMPERATURE TIME TRAVELED UP TO 400 ° C ° C ° C SECOND ° C / SECOND ° C TIME % 53 N 1215 0.23 907 3.4 26 581 3.0 57 EXAMPLE 54 N 1185 0.27 975 2.9 28 556 2.6 55 EXAMPLE 55 N 1240 0.91 934 4.6 23 556 2.2 60 EXAMPLE 56 N 1275 0.39 971 03 42 569 3.7 47 COMPARATIVE EXAMPLE 57 0 1225 0.74 966 6.3 24 590 3.5 63 EXAMPLE 58 0 1260 0.59 932 4.9 32 618 3.9 44 EXAMPLE 59 0 1235 0.39 915 4.5 25 593 3.5 46 EXAMPLE 60 0 1275 0.44 943 7.1 30 552 2.0 43 COMPARATIVE EXAMPLE 61 P 1280 0.77 948 2.4 38 608 2.7 55 EXAMPLE 62 P 1240 0.22 958 3.3 32 540 4.4 64 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 93/134
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP COLD LAMINATION STAGE CLASSIFICATION PLATE HEATING TEMPERATURE EXPRESSION 1 TEMPERATURE FORCOMPLETE THE BLADE-DOG PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RETENTION TIME UNTIL THE COOLING BEGINS AVERAGE COOLING RATE COOLING END TEMPERATURE TIME TRAVELED UP TO 400 ° C ° C ° C SECOND ° C / SECOND ° C TIME % 63 P 1255 0.49 961 3.4 34 571 2.6 57 EXAMPLE 64 P 1200 0.57 903 4.6 31 577 5.9 55 COMPARATIVE EXAMPLE 65 Q 1220 0.42 909 5.1 25 586 3.0 57 EXAMPLE 66 Q 1235 0.31 879 2.4 19 593 4.9 55 EXAMPLE 67 Q 1190 0.24 946 3.8 31 634 5.6 63 EXAMPLE 68 Q 1280 0.59 974 6.1 27 594 4.0 61 COMPARATIVE EXAMPLE 69 R 1220 0.52 960 2.3 29 508 1.4 47 EXAMPLE 70 R 1200 0.23 919 8.4 23 553 2.7 68 EXAMPLE 71 R 1265 0.35 938 1.8 35 550 2.0 63 EXAMPLE 72 R 1215 0.34 900 5.6 30 574 2.7 50 COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 94/134
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP COLD LAMINATION STAGE CLASSIFICATION PLATE HEATING TEMPERATURE EXPRESSION 1 TEMPERATURE FORCOMPLETE THE BLADE-DOG PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RETENTION TIME UNTIL THE COOLING BEGINS AVERAGE COOLING RATE COOLING END TEMPERATURE TIME TRAVELED UP TO 400 ° C ° C ° C SECOND ° C / SECOND ° C TIME % 73 s 1240 0.81 976 2.9 23 602 4.3 73 EXAMPLE 74 s 1265 0.35 950 5.6 32 566 2.3 50 EXAMPLE 75 s 1250 0.66 897 3.5 17 635 6.9 55 EXAMPLE 76 s 1030 0.42 912 5.6 35 569 2.3 43 COMPARATIVE EXAMPLE 77 T 1205 0.32 887 1.6 24 591 2.9 57 EXAMPLE 78 T 1215 0.39 876 3.7 27 592 4.3 57 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 95/134 [Table 6]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP STEP OFCOLD LAMINATION O<Oω% O TEMPERATUREHEATINGBOARD EXPRESSION 1 TEMPERATURE FORCOMPLETE LAMI-NATION PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RETENTION TIME UNTIL THE COOLING BEGINS AVERAGE COOLING RATE COOLING END TEMPERATURE TIME TRAVELED UP TO 400 <C ° C ° C SECOND ° C / SECOND ° C TIME % 79 T 1245 0.45 974 5.8 28 608 3.8 41 EXAMPLE 80 T 1215 1.27 979 7.0 39 601 4.3 50 COMPARATIVE EXAMPLE 81 U 1220 0.67 969 4.1 37 604 3.9 44 EXAMPLE 82 U 1225 0.40 954 5.0 32 578 2.3 60 EXAMPLE 83 U 1230 0.34 966 2.9 36 574 2.5 52 EXAMPLE 84 U 1225 0.45 936 2.9 26 587 0.6 40 COMPARATIVE EXAMPLE 85 V 1235 0.46 937 5.7 29 577 2.2 61 EXAMPLE 86 V 1255 0.83 920 2.4 26 609 4.9 52 EXAMPLE 87 V 1195 0.57 874 2.1 24 568 4.9 65 EXAMPLE 88 V 1255 0.23 979 2.3 34 570 2.2 42 COMPARATIVE EXAMPLE 89 W 1220 0.41 942 2.6 21 597 4.0 45 EXAMPLE 90 W 1255 0.15 937 9.1 40 551 4.6 40 EXAMPLE 91 W 1230 0.34 905 3.2 28 582 4.3 50 EXAMPLE 92 W 1200 0.71 938 2.9 34 608 3.4 45 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 96/134
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP STEP OFCOLD LAMINATION CLASSIFICATION TEMPERATUREHEATINGBOARD EXPRESSION 1 TEMPERATURE FORCOMPLETE LAMI-NATION PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RETENTION TIME UNTIL THE COOLING BEGINS AVERAGE COOLING RATE COOLING END TEMPERATURE TIME TRAVELED UP TO 400 <C ° C ° C SECOND ° C / SECOND ° C TIME % COMPARATIVE 93 X 1225 0.33 974 2.7 42 561 5.4 34 EXAMPLE 94 X 1235 0.30 897 4.2 35 518 3.1 42 EXAMPLE 95 X 1210 0.39 940 3.2 24 600 4.3 63 EXAMPLE 96 X 1255 0.73 941 0.4 24 560 2.7 52 COMPARATIVE EXAMPLE 97 Y 1220 0.44 980 6.7 40 604 4.5 45 EXAMPLE 98 Y 1225 0.35 961 1.3 25 569 5.3 52 EXAMPLE 99 Y 1205 0.74 914 4.0 29 612 2.2 46 EXAMPLE 100 Y 1260 0.72 899 5.2 28 551 3.1 57 COMPARATIVE EXAMPLE 101 Z 1265 0.61 959 2.2 40 564 5.5 39 EXAMPLE 102 Z 1270 0.34 970 7.5 48 558 1.3 47 EXAMPLE 103 Z 1225 0.45 916 2.5 26 503 1.5 61 EXAMPLE 104 Z 1255 0.08 950 3.0 37 565 2.9 54 COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 97/134 [Table 7]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP STEP OFCOLD LAMINATION CLASSIFICATION TEMPERATUREHEATINGBOARD EXPRESSION 1 TEMPERATURE FORCOMPLETE LAMI-NATION PRIMARY COOLING SECONDARY COOLING REDUCTION RATE RETENTION TIME UNTIL THE COOLING BEGINS AVERAGE COOLING RATE COOLING END TEMPERATURE TIME TRAVELED UP TO 400 ° C ° C ° C SECOND ° C / SECOND ° C TIME % 105 AA 1245 0.36 958 4.4 38 561 2.9 66 EXAMPLE 106 AA 1225 0.69 899 4.9 30 554 3.8 56 EXAMPLE 107 AA 1240 0.71 895 7.3 23 603 3.3 56 EXAMPLE 108 AA 1200 0.38 939 7.0 26 570 5.2 60 COMPARATIVE EXAMPLE 109 AB 1200 0.46 930 2.6 30 612 3.2 41 EXAMPLE 110 AB 1255 0.23 912 2.8 43 532 2.6 64 EXAMPLE 111 AB 1230 0.47 927 3.4 24 590 3.5 42 EXAMPLE 112 AB 1250 0.64 957 2.7 39 435 1.5 52 COMPARATIVE EXAMPLE 113 B.C 1255 0.39 897 2.5 21 608 3.2 35 EXAMPLE 114 B.C 1275 0.31 918 2.7 20 609 5.8 45 EXAMPLE 115 B.C 1200 0.61 974 3.9 38 554 4.4 40 EXAMPLE 116 B.C 1220 0.02 919 4.4 31 554 2.2 53 COMPARATIVE EXAMPLE 117 AD 1200 0.66 895 2.5 22 553 4.8 50 EXAMPLE 118 AD 1230 0.38 962 4.2 27 558 5.6 41 EXAMPLE 119 AD 1250 0.80 966 6.5 40 526 1.9 37 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 98/134
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT HOT LAMINATION STEP STEP OFCOLD LAMINATION CLASSIFICATION HEATING TEMPERATURE OFBOARD EXPRESSION 1 TEMPERATURE FOR COMPLETE THE NATION laminar PRIMARY COOLING SECONDARY COOLING REDUCTION RATE£ RETENTION TIMETILL THE COOLING STARTSECOND AVERAGE COOLING RATE° C / SECOND COOLING END TEMPERATURE° C TIME TRAVELED UP TO 400 ° CTIME 120 AD 1270 0.80 965 2.6 26 574 2.5 85 COMPARATIVE EXAMPLE 121 AE 1280 0.64 931 5.1 21 612 5.6 55 COMPARATIVE EXAMPLE 122 AF 1245 0.52 915 6.1 29 553 2.6 55 COMPARATIVE EXAMPLE 123 AG 1210 0.56 897 6.7 25 585 2.7 55 COMPARATIVE EXAMPLE 124 BA 1245 0.34 919 2.1 21 595 3.1 - COMPARATIVE EXAMPLE 125 BB 1245 0.29 914 3.0 27 619 4.0 40 COMPARATIVE EXAMPLE 126 BC Test Interrupted Due to Plate Crack COMPARATIVE EXAMPLE 127 BD 1240 0.56 884 1.7 20 606 3.3 60 COMPARATIVE EXAMPLE 128 BE 1245 0.30 919 2.2 25 611 2.9 47 COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 99/134 [Table 8]
EXPERIMENTAL EXAMPLE COMPONENT RECOVERY STEP - ELECTRODEPOSITION STEP THIRD STEPINRES- TEMPERING STEP CORRECTIVE LAMINATIONSTEEL TYPE HEATING STEP FIRSTSTEP OFCOOLTO MONDAYSTEP OFCOOLTO BAINITA TRANSFORMATION PROCESS PROPORTION OF MIXED GAS IN THE PRE-HEATING AREA AT THE/ 2> o * Ό mI OO ELECTRODEPOSITION ZONE SUPPLY OVENALLOY APPLE COLD-MENT CLASSIFICATION CHEMICAL HEATING RATE-600 CEMENTUP TO 750 ° C MAXIMUM TEMPERATURE OFHEATING HEATING RATE TO 600 TO 750 ° C COOLING RATE DEPARTINGFROM 650 ° C RETENTION TIME AT 300 TO 470 ° C QUANTITY OF EFFECTIVE AL TEMPERA-TURE OFBATH OFELECTRO-DEPOSIT-DOG TEMPERATURESTEEL PLATE ENTRY TEMPERATUREALLOY FORMATION TIME TOTREATMENT RATE OFRES-COOLING TEMPERATURE TEMPERATURE REDUCTION RATE ° C / SECOND ° C ° C / SECOND ° C / SECOND SECOND% IN LARGE SCALE ° C ° C ° C SECOND ° C / FOLLOW ° C %1 THE GT ^- 4.8 835 3.6 5, 7 - 0.7 0.562 0.09 458 472 - - 1.8- EXAMPLE 2 THE GI 7.4 757 6.3 41.6 115 0.9 0.023 0.10 455 ° C - - 3.7 - - EXAMPLE 3 THE GA 2.0 849 1.9 19.5 48 1.0 0.017 0.10 452 446 490 29 2.4 - 0.20 EXAMPLE 4 THE" GT 8.7 852 4.3 26.5 - 0.9 0.126 0.11 465 463 - - 2.7 - - COMPARATIVE EXAMPLE 5 B GI 7.4 893 2.2 4.0 - 1.0 0.214 0.11 461 476 - - 2.5 - - EXAMPLE 6 B GA 10.5 835 5.9 34.7 37 1.2 0.005 0.11 463 459 532 15 1.4 - - EXAMPLE 7 B GA 4.4 887 3.9 13.6 40 1.0 0.025 0.11 466 453 519 10 2.8 - - EXAMPLE 8 B GA 8.6 870 7.0 9.8 30 0.9 0.195 0.11 453 447 635 28 3.8- EXAMPLECOMPARATIVE —9— Ç" GT 6.5 809 6.5 8.9 101 0.9 0.117 0.10 453 445 - - 3.8 - - EXAMPLE 10 Ç GA 4.1 805 4.8 5.2 - 1.0 0.013 0.08 463 468 492 30 0.8 - - EXAMPLE 11 Ç GA 2.2 884 4.8 7.7 349 1.0 0.219 0.07 465 448 477 18 32.4 - - EXAMPLE T2 ~ Ç" GT 6.1 833 3.5 0.9 - 0.8 1.00 0.11 462 460- 3.6 - - COMPARATIVE EXAMPLE 13 D GI 5.1 805 5.4 40.2 44 0.8 0.078 0.10 461 470 - - 3.1 - - EXAMPLE 14 D GI 9.5 790 7.4 51.4 40 0.8 0.062 0.11 459 468 -22.0- EXAMPLE 15 D GA 2.2 824 6.4 6.0 - 1.0 0.012 0.08 463 471 498 10 2.3- EXAMPLE 16 D GI 10.2 835 3.1 5.0 40 1.1 0.0000 0.12 465 446 - - 1.0 - - COMPARATIVE EXAMPLE 17 AND GI 5.6 844 3.7 6.2 - 0.8 0.166 0.08 469 484 - - 3.6 - - EXAMPLE 18 -AND" GA 5.3 824 4.3 13.5 140 1.0 0.020 0.07 467 463 567 27 4.1 290 - EXAMPLE 19 AND GA 6.0 973 5.8 8.3 94 0.9 0.018 0.09 459 434 521 24 3.8 - - EXAMPLE 20 AND GI 5.8 868 26.0 20.0 84 1.0 0.200 0.08 451 443 - - 3.6 - - COMPARAT IVO EXAMPLE 21 F GI 6.6 817 5.6 6.2 36 0.9 0.006 0.09 456 441 - - 3.2 - - EXAMPLE 22 F GA 13.8 821 4.5 3.3 292 1.0 0.100 0.07 460 457 463 20 40.0 - - EXAMPLE 23 F GA 6.0 862 2.6 17.4 52 0.8 0.030 0.09 453 463 612 5 4.1 - - EXAMPLE 24 F GI 2.2 804 1.6 13.5 45 1.1 0.020 0.10 459 472 - -- - COMPARATIVE EXAMPLE 25 G GI 5.1 848 5.9 6.9 - 0.8 0.145 0.10 457 472 - - 2.8 - - EXAMPLE 26 G GI 5.3 877 3.7 12.8 - 0.9 0.240 0.07 464 486 - - 3.5 410 - EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 100/134 [Table 9]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE E1 RECOZING APA - STEP OF IT 1 RODEPOSITION THIRD COOLING STEP AND T TEMPERATURE CORRECTIVE LAMINATION CLASSIFICATION HEATING STEP FIRST COOLING STAGE SECOND COOLING STAGE BAINITA TRANSFORMATION PROCESS PROPORTION OF MIXED GAS IN THE PREA-HEATING Reduction Zone ELECTRODEPOSITION ZONE ALLOY TRAINING OVEN HEATING RATE TO 600 TO 750 ° C MAXIMUM TEMPERATURE OFHEATING COOLING RATE AT 750 ° C TO 650 ° C COOLING RATE DEPARTINGFROM 650 ° C TIME TORETENTION AT 300 UNTILTO 470 ° C AMOUNTFROM EFFECTIVE AL Electrodeposition Bath Temperature TEMPERATUREFROM THE ENTRANCE OF THE PLATESTEEL ALLOY FORMATION TEMPERATURE TREATMENT TIME COOLING RATE TEMPERATURE TEMPERATURE REDUCTION RATE ^w / SECOND ^c C ^w / SECOND ^w / SECOND SECOND% IN LARGE SCALE ° C ° C ° C SECOND ° C / SECOND% 27 G GA 3.1 879 5.0 7.5 51 1.1 0.148 0.09 460 462 483 10 3.0 - 0.20 EXAMPLE 28 G GI 28 828 6.0 18.0 69 1.2 0.072 0.10 454 445 -0.9 - - COMPARATIVE EXAMPLE 29 H GI 1.1 844 5.3 107.2 50 1.0 0.015 0.10 462 463 - - 2.0 - - EXAMPLE 30 H Gl 4.7 796 2.6 4.6 - 1.2 0.0006 0.07 456 481 - -- - EXAMPLE 31 H GA 6.6 839 4.0 5.7 100 0.9 0.145 0.08 462 447 536 23 3.4 - - EXAMPLE 32 H Gl 3.2 795 8.2 17.7 - 0.9 0.093 0.11 466 479 - - 0.2 -COMPARATIVE EXAMPLE 33 I Gl 10.8 853 6.9 6.5 121 0.9 0 024 0.09 469 459 - - 3.5 - - EXAMPLE 34 I GA 1.8 777 3.4 8.1 - 0.8 0.072 0.09 464 477 589 9 1.9 - - EXAMPLE 35 I GA 5.4 857 3.4 6.2 - 1.0 0.126 0.10 454 473 508 46 53.8 250 - EXAMPLE 36 I GI 3.8 842 1.8 21 8 83 1.1 0.035 0.09 468 450 -3.7 - - COMPARATIVE EXAMPLE 37 J GI 5.6 831 2.7 4.1 240 1.1 0.066 0.10 457 439 -4.1 - 0.10 EXAMPLE 38 J GA 6.7 758 12.6 6.2 93 0.9 0.117 0.08 456 460 520 7 2.4 - - EXAMPLE 39 J GA 8.0 809 3.6 45.7 297 1.0 0.003 0.08 467 467 496 18 3.0 - - EXAMPLE 40 J Gl 5.8 892 4.7 26.0 78 0.8 0.158 0.08 453 456 - - 1.0 - - COMPARATIVE EXAMPLE 41 —K “ GT 6.3 787 3.9 4.1 - 0.7 0.977 0.10 460 476 - - 2.2 - 0.1 EXAMPLE 42 K Gl 3.9 817 5.2 15.2 80 0.9 0.083 0.15 455 436- 2.5 - - EXAMPLE 43 K GA 8.6 828 4.7 13.9 28 1.0 0.081 0.10 459 465 540 14 2.7 - - EXAMPLE 44 K Gl 31 779 3.9 18.4 - 1.0 0.005 0.10 466 484 - - 1.6 -COMPARATIVE EXAMPLE 45 L Gl 3.9 916 8.4 4.8 132 0.7 0.006 0.12 455 447- 4.4 - - EXAMPLE 46 L GA 17.4 789 7.5 15.3 - 1.1 0.135 0.10 467 479 515 11 2.6 -EXAMPLE 47 L GA 5.4 798 5.5 8.9 50 1.0 0.182 0.08 466 445 480 115 4.4 - - EXAMPLE 48 L Gl 8.3 842 7.5 20.2 - 0.8 0.191 0.11 462 474 - - 2.0 - - COMPARATIVE EXAMPLE 49 M Gl 7.1 884 3.1 7.0 96 08 0.041 0.18 455 456 - - 4.4 - - EXAMPLE 50 M GT 4.7 829 3.4 38 9 64 09 0.001 0.08 457 469 - - 1.7 - - EXAMPLE 51 M GA 5.1 888 3.9 24.4 60 0.8 0.141 0.10 468 466 510 27 1.4 - - EXAMPLE 52 M Gl 5.4 875 8.2 17.2 71 0.4 0.005 0.07 466 457 - - 2.5 - - COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 101/134 [Table 10]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE RECOVERY STEP - ELECTRODEPOSITION STEP THIRD COOLING STEP TEMPERING STEP CORRECTIVE LAMINATION CLASSIFICATION HEATING STEP FIRSTSTEP OFCOOLTO MONDAYSTEP OFCOOLTO BAINITA TRANSFORMATION PROCESS Proportion of Gas Mix in the Pre-Heating Zone At theX σΊΙο ELECTRODEPOSITION ZONE SUPPLY OVENALLOY APPLE HEATING RATE 600 TO 750OC MAXIMUM HEATING TEMPERATURE COOLING RATETO 750 ° CUP TO 650 ° C COOLING RATE DEPARTINGFROM 650 ° C RETENTION TIME 300 TO 470OC Amount of Al Effective Electrodeposition Bath Temperature Steel Sheet Inlet Temperature TEMPERATUREALLOY FORMATION TIME TOTREATMENT COOL RATE-MENT TEMPERATURE OFWAIT RATE OFREDUCTION ° C / SECOND Ç ° C / SECOND ° C / SECOND SECOND the o% IN LARGE SCALE ° C ° C ° C SECOND ° C / SECOND Ç % 53 N GI 8.7 838 3.0 3.60.9 0.008 0.10 463 473 -3.0 - - EXAMPLE 54 N GA 3.6 897 5.1 20.0 483 1.1 1.12 0.12 458 454 537 10 3.4 - - EXAMPLE 55 N GA 1.4 808 11.4 6.2 30 0.9 0.141 0.09 457 466 504 20 2.0 - - EXAMPLE 56 N GI 7.7 914 3.0 7.2 97 1.0 0.122 0.12 458 455 - - 3.5 - - COMPARATIVE EXAMPLE 57 O GI 7.8 800 3.1 7.5 74 0.9 0.003 0.11 462 450 - - 2.8 - - EXAMPLE 58 O GI 11.4 763 6.2 19.00.9 0.251 0.11 457 474 - - 1.5 330 - EXAMPLE 59 O GA 7.3 878 3.4 5.61.1 0.006 0.11 458 476 473 72 1.0 - - EXAMPLE 60 O GI 3.2 894 7.5 22.4 308J * 0.8 0.012 0.09 463 448 - - 1.8 - - COMPARATIVE EXAMPLE 61 P Gl 9.9 842 7.3 5.5 83 0.9 0.003 0.09 457 457 - - 3.8 - - EXAMPLE 62 P GA 1.2 810 9.4 38.9 51 0.9 1.34 0.09 463 450 557 10 3.0 - 0.05 EXAMPLE 63 P GA 9.7 813 6.7 18.2 50 1.0 0.044 0.09 462 456 533 14 2.8 - - EXAMPLE 64 P GI 3.5 873 4.6 9.1 58 1.8 0.006 0.10 458 465 - - 1.8- COMPARATIVE EXAMPLE 65 Q Gl 7.2 920 4.3 6.2 40 1.0 0.105 010 466 460- 4.2 - - EXAMPLE 66 Q GA 13.0 909 4.2 86.50.9 0.871 0.09 458 475 584 13 10.8 - - EXAMPLE 67 Q GA 1.9 802 5.6 16.8 164 1.1 0.046 0.11 465 439 483 36 4.2 - - EXAMPLE 68 Q Gl 5.7 709 5.9 15.3 - 1.0 0.023 0.11 458 455 - - 2.0 - - COMPARATIVE EXAMPLE IVO 69 R Gl 4.1 861 2.0 5.4 - 0.8 0.002 0.07 464 480 - - 3.8 - - EXAMPLE 70 R GA 6.3 842 5.5 51.6 90 0.8 0.174 0.08 466 457 541 25 2.9 - 0.80 EXAMPLE 71 R GA 9.9 786 2.1 22.7 67 0.9 0.324 0 09 463 446 484 18 28- EXAMPLE 72 R GI 9.6 879 5.165 0.9 2.40 0.12 465 458 - - 4.7 - - COMPARAT IVO EXAMPLE 73 s GI 6.1 840 3.6 22.4 84 0.9 0.009 0.17 457 460 - - 3.9 - - EXAMPLE 74 s GA 3.9 883 2.5 118.7 139 1.1 0.026 0.09 459 443 497 25 42.3 340 - EXAMPLE 75 s GA 2.9 894 1.3 41.6 29 0.8 0.759 0.10 452 471 514 41 1.3 - - EXAMPLE 76 s GI 4.1 850 7.5 16.8 76 0.9 0.155 0.10 465 451- 4.2 -COMPARATIVE EXAMPLE 77 T GI 8.5 796 6.2 92.7 91 1.0 0.011 0.10 466 464 - - 3.2 - - EXAMPLE 78 T GA 11.2 850 4.6 24 7 88 0.9 0.085 0.07 482 478 520 30 3.5 - - EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 102/134 [Table 11]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE RECOVERY STEP - ELECTRODEPOSITION STEP THIRD COOLING STEP TEMPERING STEP CORRECTIVE LAMINATION CLASSIFICATION HEATING STEP FIRST COOLING STAGE SECOND COOLING STAGE BAINITA TRANSFORMATION PROCESS PROPORTION OF MIXED GAS IN THE PRE-HEATING AREA AT THE>πmIG> o ELECTRONOPOSITION ZONE ALLOY TRAINING OVEN HEATING RATE TO 600 TO 750 ° C MAXIMUM HEATING TEMPERATURE COOLING RATE AT 750 ° C UNTIL650 ° C COOLING RATE DEPARTINGFROM 650 ° C RETENTION TIME A300 TO 470 ° C QUANTITY OF EFFECTIVE AL ELECTRODEPOSITION BATH TEMPERATURE INPUT TEMPERATURE OF PLATESTEEL ALLOY FORMATION TEMPERATURE TREATMENT TIME COOLING RATE TEMPERATURE TEMPERATURE REDUCTION RATE ° C / SECOND ° C ° C / SECOND ° C / SECOND SECOND% IN LARGE SCALE ° C ° C t SECOND ° C / SECOND ° C79 1 GA 6.5 848 6.2 63 172 0.9 0.006 0.10 456 463 515 30 3.0 EXAMPLE 80 T GI 6.6 837 2.9 20.8 86 1.2 0.562 0.08 460 449 - - 2.8 - - COMPARATIVE EXAMPLE 81GI 6.2 792 3.5 66.0 228 0.7 0.034 0.14 461 466 -2.0 - - EXAMPLE 82 U GI 0.7 864 2.8 21.5 236 0.9 0.036 0.09 454 486 -0.8 - 0.60 EXAMPLE 83 U GA 2.7 827 5.9 6.7 257 0.9 0.016 0.10 462 433 498 26 1.8 - - EXAMPLE 84 U GI 3.8 840 7.3 12.5 220 0.9 0.032 0.12 461 475 -3.6- COMPARATIVE EXAMPLE 85 V ~~ GT “ 4.4 834 4.7 6.0 56 1.1 0.066 0.03 469 461 - - 3.0 -EXAMPLE 86 V GI 4.8 877 3.7 24.5 140 1.2 0.017 0.08 453 473 - - 2.7 - - EXAMPLE 87 V GA 9.3 857 4.5 17.1 130 0.9 0.054 0.10 458 457 500 10 2.8 - - EXAMPLE 88 —V ~ GF 7.5 888 1.8 6.2 59 1.1 0.324 0.29 461 447 - - 1.9 - - COMPARATIVE EXAMPLE 89 W GI 4.6 362 4.1 43.7 95 0.8 0.145 0.06 460 477 - - 3.3 - - EXAMPLE 90 W GI 6.2 785 3.0 52.0 82 0.7 1,380 0.09 458 475 - - 3.5 - - EXAMPLE 91 W GA 4.8 822 1.4 6.6 - 0.8 0.004 0.10 465 479 507 9 2.5 - - EXAMPLE 92 W GI 6.9 830 0.3 16.0 72 1.1 0.141 0.09 457 452 3.1 - - COMPARATIVE EXAMPLE 93 X GI 3.6 769 2.9 26.5 110 1.0 0.048 0.10 465 446 - - 2.9 - - EXAMPLE 94 X GT “ 0.9 845 4.1 31.5 103 1.0 0.302 0.02 456 444 - - 3.4 - - EXAMPLE 95 X GA 3.3 878 1.2 5.7 83 0.9 0.257 0.12 467 469 527 15 3.3 - - EXAMPLE 96 X GI 4.7 836 2.4 7.5 64 0.9 0.069 0.09 456 457 - - 3.1 - - COMPARATIVE EXAMPLE 97 Y GI 8.6 841 2.9 16.5 37 0.9 0.019 0.09 457 451 - - 1.8- EXAMPLE 98 Y GA 7.9 832 7.5 47.9 47 1.2 0.056 0.12 454 468 530 23 21.9 - - EXAMPLE 99 Y GA 8.6 837 6.8 4.6 27 0.9 0.079 0.08 464 448 570 23 2.1 - - EXAMPLE 100 Y GA 5.3 859 3.3 23.8 32 0.9 0.083 0.11 462 452 498 253 3.3 - - COMPARATIVE EXAMPLE 101 Z GI 8.4 812 4.9 16.5 - 1.0 0.174 0.11 459 475 -4.1 - - EXAMPLE 102 Z GA 4.0 610 6.5 4.3 68 0.8 0.005 0.09 453 448 550 25 3.5 - - EXAMPLE 103 Z GA 8.0 864 8.5 5.6 69 1.1 0.013 0.10 461 462 483 27 2.6 - - EXAMPLE 104 Z GI 6.7 860 6.2 8.3 70 0.9 0.071 0.09 457 443 - - 3.6 - - COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 103/134 [Table 12]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE RECOVERY STEP - ELECTRODEPOSITION STEP THIRD COOLING STEP TEMPERING STEP CORRECTIVE LAMINATION CLASSIFICATION HEATING STEP FIRSTSTEP OFCOOLTO MONDAYSTEP OFCOOLTO BAINITA TRANSFORMATION PROCESS PROPORTION OF MIXED GAS IN THE PRE-HEATING AREA REDUCTION ZONEP (H2O) / P (H2) ELECTRODEPOSITION ZONE FORM OVEN-ALLOY TION HEATING RATE TO 600 TO 750 ° C TEMPERATU-MAXIMUM RA HEATING COOLING RATE AT 750 ° C TO IS 650 ° C COOLING RATE DEPARTINGFROM 650 ° C RETENTION TIME AT 300 TO 470 ° C AMOUNTFROM EFFECTIVE AL ELECTRODEPOSITION BATH TEMPERATURE STEEL PLATE INPUT TEMPERATURE ALLOY FORMATION TEMPERATURE TREATMENT TIME COOLING RATE TEMPERATURE TEMPERATURE REDUCTION RATE ° C / SECOND ° C ° C / SECOND ° C / SECOND SECOND% IN LARGE SCALE ° C ° C ° C SECOND ° C / SECOND ° C % 105 AA GI 7.1 819 2.0 9.1 294 0.9 0.219 0.11 466 456 -0.6- EXAMPLE 106 AA GI 8.4 805 6.9 43.3 284 1.0 1.59 0.03 458 466 -12.6 - - EXAMPLE 107 AA GA 3.0 800 5.6 7.0 49 1.1 0.224 0.11 454 460 518 16 3.6 - - EXAMPLE 108 AA GI 7.6 825 5.6 4.9 79 1.0 0.234 0.00 458 444 - - 3.8- COMPARATIVE EXAMPLE TO9 ^- AB GI 1.3 827 5.2 4.9 41 1.0 0.033 0.12 459 454 - - 19 - - EXAMPLE 110 AB GA 0.8 811 2.6 21.5 43 1.0 0.178 0.07 453 471 525 21 3.0 - - EXAMPLE 111 AB GA 1.5 804 7.1 48.8 46 0.8 0.004 0.09 461 467 496 41 3.5 - - EXAMPLE 112 AB GI 1.5 857 1.3 22.4 50 0.9 0.004 0.08 459 462- 2.5 - - Comparative EXO PLO 113 B.C GI 2.9 892 5.3 6.1 25 0.9 0.071 0.07 453 459- 3.6- EXAMPLE 114 B.C GA 2.5 910 2.9 27.2 160 1.0 0.019 0.10 455 434 514 20 4.6 - - EXAMPLE 115 B.C GA 4.7 872 3.8 21.9 193 0.8 0.398 0.08 458 463 487 34 07 - - EXAMPLE 116 B.C GI 6.5 886 6.8 7.1 130 0.8 0.012 0.08 461 487- 29 - - COMPARATIVE EXAMPLE 117 AD GI 8.1 829 4.8 3.4 32 1.0 0.025 0.10 466 463 - - 3.0 - - EXAMPLE 118 AD GA 1.6 910 8.3 19.4 25 0.9 0.050 0.11 464 477 540 15 1 9 - - EXAMPLE 119 AD GA 6.0 825 5.5 19.6 - 1.1 0.012 0.11 464 475 508 18 29 - - EXAMPLE 120 AD GI 3.1 848 31 4.0 - 0.9 0.136 0.10 468 472 - - 5.9 - - COMPARATIVE EXAMPLE 121 AE GI 5.9 841 8.3 4.9 42 0.9 0.018 0.09 461 460 - - 2.2- Comparative EXO PLO 122 AF GI 4.9 837 5.7 6.9 50 1.1 0.076 0.11 454 449 - - 31 - - Comparative EXO PLO 123 AG GI 2.8 833 6.8 7.8 40 1.1 0.015 0.12 456 456 - - 3.7 - - Comparative EXO PLO 124 BAINTERRUPTED TEST DUE TO FRACTURE AT THE LAM STEP NATION A F = IO Comparative EXAMPLE 125 BB GA 3.4 814 1.4 ¹⁴ , 7 ⁶³ 0.9 0.200 0.10 466 ^{470 497 20} 2.3 ^{- -} Comparative EXO PLO 126 BCINTERRUPTED TEST DUE TO PLATE CRACKING COMPARATIVE EXAMPLE 127 BDINTERRUPTED TEST DUE TO FRACTURE OF THE WELDING ZONE AT THE CAIRING STEP Comparative EXAMPLE 128 BE GA 2.5 805 1.9 ¹⁵ , 3 106 1 1.4 0.158 0.08 ^{463 461} 536 ²⁰ 2.9 - ^- COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 104/134 [Table 13]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE BASE STEEL SHEET MICROESTRUT URA SURFACE LAYER(DECARBURIZED LAYER) BASE STEEL SHEET PROPERTY CLASSIFICATION STRUCTURAL FRACTION FERRITA STRUCTURE-TURARIGID RATIO OF RANDOM INTENSITY OF BCC IRON X-RAY INCLUSION DECARBURIZED LAYER THICKNESS OXIDE DENSITY 10'2 OXIDES / m ² OXIDE SIZEç EXTERNAL APPEARANCE TRACTION PROPERTY RESISTANCE TO LATE FRACTURE FERRITA BAINITA BAINITIC FERRITA£ MARTENSITE MARTENSITE TEM-PERRY AUSTENITE WITHHELD OTHERS d (RD)/ d (TD) FERRITE FRACTION NOT RECRISTALIZED L (RD) / L (TD) ASPECT PROPORTION D (RD) / D (TD) FLOW LIMIT-MENT5 TENSION RESISTANCEG5 CL 5 TOTAL STRETCH VALUE N Des _C ASCAMENTO OF electrodeposition ACID IMMERSION TEST RESULT LIMIT DIFFUSIBLE HYDROGEN CONTENT 1 THE Gl 55 13 10 16 2 3 1 0.93 0 0.93 2.4 3.0 1.26 3.45 43.0 73 O 679 1178 16 0.087 - O 1.23 EXAMPLE 2 THE Gl 65 14 12 6 0 1 2 1.08 0 0.91 2.8 3.4 1.69 0.94 9.5 78 O 443 948 22 0.136 - O 0.73 EXAMPLE 3 THE GA 66 25 0 7 0 0 2 0.90 0 0.98 3.0 2.7 1.12 0.67 23.3 61 O 654 1126 17 0.117 - O 1.60 EXAMPLE 4 THE Gl 53 18 5 19 1 4 0 0.96 0 0.90 2.4 6.3 3.02 3.22 38.3 66 O 719 1212 16 0.101 - x 3.40 COMPARATIVE EXAMPLE 5 ~~ B “ Gl 52 12 "26" —R ~ ~ 0 ” 1 ~~ 2 ~ 0.82 —0 “ 1.02 3.2 4.1 1.64 2.63 4.9"O ^- 703 1183 16 0.095 - ~~ O ~ 1.18 EXAMPLE 6 B GA 49 31 18 0 0 2 0 1.05 0 0.97 3.0 2.7 1.41 0.45 6.8 63 O 583 989 21 0.125 - O 1.10 EXAMPLE 7 B GA 51 24 20 4 0 0 1 1.18 0 1.03 2.7 3.8 1.38 0.97 9.0 74 O 653 1131 17 0.097 - O 1.45 EXAMPLE 8 B GA 47 37 5 0 0 0 11 0.90 0 0.87 2.9 3.6 1.24 3.42 19.4 79 ~ O ~ 494 807 28 0.147 EXISTENCE O 1.25 COMPARATIVE EXAMPLE 9 Ç Gl 65 0 28 4 0 3 0 0.95 0 0.92 3.1 3.8 1.55 2.93 60.9 65 O 479 960 22 0.140 - O 1.07 EXAMPLE 10 Ç GA 78 2 14 6 0 0 0 1.07 0 1.23 3.4 3.5 1.63 1.00 8.3 44 O 322 918 23 0.165 - O 1.28 EXAMPLE 11 ~~ C ~ GA 59 5 "26" "8" ~ 0 “ ~~ 2 ~ ~ 0 ” 0.91 —0 “ 1.05 3.2 3.1 1.66 2.77 177.1 51 ~~ O ~ 602 1091 18 0.111 - ~~ O ~ 1.48 EXAMPLE 12 Ç Gl 73 2 17 0 0 0 8 0.90 0 1.06 3.6 3.3 1.47 4.37 50.4 75 O 375 764 30 0.214 - O 1.32 COMPARATIVE EXAMPLE 13 D Gl 51 23 17 8 1 0 0 1.03 0 0.89 2.7 3.5 1.57 2.69 20.4 62 O 794 1130 17 0.092 - O 1.52 EXAMPLE 14 D Gl 49 20 21 7 0 1 2 0.98 0 0.97 2.7 3.1 1.68 2.34 17.1 67 O 810 1166 16 0.092 - O 0.86 EXAMPLE 15 D GA 48 22 15 8 1 3 3 1.12 0 1.06 2.6 3.4 1.59 0.88 6.2 81 O 844 1353 13 0.081 - O 1.60 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 105/134 [Table 14]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE BASE STEEL SHEET MICRO-STRUCTURE SURFACE LAYER (DECARBURIZED LAYER)BASE STEEL SHEET PROPERTY CLASSIFICATION STRUCTURAL FRACTION FERRITA STRUCTURE-TURARIGID RATIO OF RANDOM INTENSITY OF BCC IRON X-RAY INCLUSION DECARBURIZED LAYER THICKNESS DENSITY OFOXIDE10'2 OXIDES / m2 OXIDE SIZEç EXTERNAL APPEARANCE TRACTION PROPERTY DELAYED FRACTURE RESISTANCE FERRITA£ BAINITA£ BAINITIC FERRITA£ MARTENSITE£ TEMPERED MARTENSITE£ AUSTENITE WITHHELD£ OTHERS D (RD) / D(TD) FERRITE FRACTION NOT RECRISTALIZED ° L (RD) / L (TD) ASPECT PROPORTION D (RD) / D (TD) FLOW LIMITG5 CL 5 m toto-1mzO>-1§ O> oMPa TOTAL STRETCH£ VALUE N ELECTRODE DEPELLINGPOSITION RESULTS OF THE CHLORIDIC ACID IMMERSION TEST LIMIT DIFFUSIBLE HYDROGEN CONTENT 16 D GI 46 22 20 I2 0 0 0 1.00 0 1.06 3.0 3.2 1.37 0.00 <1.0 28 X 823 1260 14 0.075X 0.99 COMPARATIVE EXAMPLE 17 AND Gl 83 0 7 8 0 1 1 0.89 0 0.92 2.9 3.3 1.76 2.19 110.7 53 O 350 852 26 0.199 - O 1.01 EXAMPLE 18 AND GA 73 12 10 0 5 0 0 1.13 0 1.00 2.9 2.9 1.43 1.39 39.3 58 O 429 880 25 0.165 - O 0.95 EXAMPLE"AND" GA 61 ^ 13 ” 15 "8" "Ü" 3 "0" 1.01 0 " 1.00 3.6 2.6 1.27 1.45 110.8 "34" ~ O ~ 582 1131 17 0.104 - O 1.31 EXAMPLE 20 AND GI 17 28 19 31 0 2 3 1 02 0 1.09 2.0 3.6 1.47 3.17 129.5 53 O 1219 1513 11 0.048 - O 1.05 COMPARATIVE EXAMPLE 21 F Gl 53 8 27 9 0 1 2 1 12 0 0.95 2.8 3.8 1.76 0.82 44.7 48 O 766 1320 13 0.072 - O 0.86 EXAMPLE 22 F GA 45 17 26 6 2 4 0 0.89 6 0.92 3.1 3.4 0 74 1.89 61.0 64 O 850 1374 13 0.078O 0 87 EXAMPLE 23 F GA 56 28 10 3 0 1 2 1.02 0 1.06 2.6 3.1 1.70 2.15 46.7 63 O 664 1244 15 0.087O 1.09 EXAMPLE 24 F GI 64 23 7 5 0 0 1 1.24 0 0.98 4.3 3.0 1.17 0 66 31.9 58 O 512 1116 17 0 101O 0.48 COMPARATIVE EXAMPLE IVO 25 G Gl 52 4 20 20 0 3 1 1.02 0 1.06 2.9 4.5 1.51 2.39 110.0 47 O 884 1355 13 0.074 - O 1.43 EXAMPLE 26 G Gl 46 5 7 0 40 2 0 1.11 0 0.83 2.6 3.1 1.34 3.53 669.6 26 O 1183 1354 13 0.075 - O 0.96 EXAMPLE 27 G GA 50 11 26 9 0 2 2 1.15 0 1.00 3.1 3.1 1.21 1.53 125.8 52 O 1112 1407 12 0.073 - O 1.17 EXAMPLE 28 G Gl 51 6 32 10 0 0 1 0.95 56 1.12 3.4 4.2 1.57 1.24 68.5 59 O 1013 1292 10 0.058 - O 1.56 COMPARATIVE EXAMPLE 29 H Gl 64 10 17 8 0 0 1 1.03 0 1.16 3.0 3.9 1.85 0.85 3.0 61 O 636 1080 IS 0.108 - O 0.78 EXAMPLE 30 ~~ FT “GT 85 "Ü" 11 ~~ 4 ~ "Ü" "Ü" "Ü" 1.17 ~~ 0 “ 0.95 3, 7 1.9 1.31 0.06 1.3 "34" ~~ O ~ 406 923 23 0.162 - -O- 1.19 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 106/134 [Table 15]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE BASE STEEL SHEET MICRO-STRUCTURE SURFACE LAYER (DECARBURIZED LAYER)BASE STEEL SHEET PROPERTY CLASSIFICATION STRUCTURAL FRACTION FERRITA ESTRUTIVRRIGID RATIO OF RANDOM INTENSITY OF BCC IRON X-RAY INCLUSION DECARBURIZED LAYER THICKNESS OXIDE DENSITY 10 ¹² OXIDES / m ² OXIDE SIZEç EXTERNAL APPEARANCE TRACTION PROPERTY RESISTANCE TO LATE FRACTURE FERRITA£ BAINITA BAINITIC FERRITA£ MARTENSITE£ TEMPERED MARTENSITE£ AUSTENITE WITHHELD£ OTHERS D (RD) / D (TD) FERRITE FRACTION NOT RECRISTALIZED ° L (RD)/ L (TD) ASPECT PROPORTION D (RD) / D (TD) FLOW LIMITG5 CL 5 TENSION RESISTANCEG5 CL 5 TOTAL STRETCH£ VALUE N ELECTRIC STRIPPINGDEPOSITION RESULTS OF THE CHLORIDE ACID IMMERSION TEST LIMIT DIFFUSIBLE HYDROGEN CONTENT 31 H GA 68 25 7 0 0 0 0 0.91 0 1.17 3.3 2.9 1.45 3.08 35.0 63 O 521 944 22 0.154 - O 1.19 EXAMPLE 32 H Gi 65 15 10 2 0 1 7 0.95 0 1.01 3.2 3.5 1.52 1.95 46.0 60 O 471 841 26 0.176 - O 0.65 COMPARATIVE EXAMPLE 33 i Gl 72 5 17 6 0 0 0 1.07 0 1.06 3.1 4.5 1.30 1.72 42.7 51 O 432 966 19 0.137 - O 0.99 EXAMPLE 34 I GA 65 "24" —R ~ "0" "0" 3 Γ “ 1.12 0 " 1.22 2.9 3.5 1.32 2.65 29.9 "66" ~ O ~ 516 1000 19 0.128 - O 1.82 EXAMPLE 35 I GA 71 3 14 0 10 2 0 0.84 0 1.14 3.1 3.6 1.16 1.85 37.7 64 O 565 1036 18 0.130 - O 0.89 EXAMPLE 36 i GI 64 5 21 8 0 1 1 1.26 0 1.41 4.1 3.0 1.64 1.11 22.0 71 O 456 976 18 0.109 - O 0.46 COMPARATIVE EXAMPLE 37 J Gl 60 15 15 5 0 4 1 0.97 0 1.05 3.2 3.4 1.56 1.46 9.9 90 O 805 1019 21 0.143 - O 1.45 EXAMPLE 38 J GA 52 24 14 6 0 1 3 1.09 0 1.04 2.9 3.5 1.36 2.27 12.3 82 O 616 1084 18 0.113 - O 0.74 EXAMPLE 39 J GA 52 22 20 4 0 0 2 1.08 0 1.02 3.3 3.8 1.32 0.17 5.6 70 O 647 1085 18 0.111 - O 1 11 EXAMPLE 40 J GI 51 19 21 7 0 0 2 1.04 0 1.06 2.7 3.9 1.50 2.69 23.7 68 X 708 1209 15 0.084O 1.21 COMPARATIVE EXAMPLE 41 K Gl 64 21 10 4 0 1 0 1.07 0 1.17 3.0 3.4 1.25 8.20 8.1 109 O 608 1003 21 0.131 - O 1.80 EXAMPLE 42 K Gl 60 20 14 4 0 1 1 1.00 0 1.01 2.7 4.5 1.45 1.84 14.1 78 O 526 1053 19 0.123 - O 1.05 EXAMPLE 43GA 58 25 ^ Tü ” 5 "0" ~~ "0" 1.12 0 0.83 3.0 3.3 1.49 2.34 7.5 83 ~~ O ~ 549 1011 20 0.118O 1.56 EXAMPLE 44 K Gl 60 13 7 14 0 3 3 1.39 54 1.52 4.3 3.2 1.41 0.85 7.5 66 O 1033 1204 9 0.053 - O 0.29 COMPARATIVE EXAMPLE 45 L Gl 44 21 21 13 0 0 1 1.13 0 1.05 2, 6 2.8 1.52 0.72 19.4 56 O 866 1414 12 0.059 - O 1.01 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 107/134 [Table 16]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE BASE STEEL SHEET MICROESTRUT URA SURFACE LAYER (DECARBURIZED LAYER)BASE STEEL SHEET PROPERTY CLASSIFICATION STRUCTURAL FRACTION FERRITA STRUCTURE URA RIGIDA RATIO OF RANDOM INTENSITY OF BCC IRON X-RAY INCLUSION DECARBURIZED LAYER THICKNESS AND OXIDE DENSITY 10 ¹² OXIDES / m ² OXIDE SIZEç EXTERNAL APPEARANCE TRACTION PROPERTY RESISTANCE TO LATE FRACTURE FERRITA£ BAINITA£ BAINITIC FERRITA£ MARTENSITE£ TEMPERED MARTENSITE£ AUSTENITE WITHHELD£ OTHERS£ D (RD) / D (TD) NO FERRITE FRACTIONRECRISTALIZED L (RD)/ L (TD) ASPECT PROPORTION D (RD)/ D (TD) FLOW LIMIT TENSION RESISTANCE TOTAL STRETCH£ VALUE N PEELING OF THEELECTRODEPOSITION RESULT OF THE CLOVER ACID IMMERSION TEST DIFFUSIBLE HYDROGEN CONTENTLIMIT 46 L GA 42 11 12 23 5 4 3 1.02 16 1.28 2.6 4.0 1.24 2.29 4.2 87 O 890 1316 14 0.078 - O 1.24 EXAMPLE 47 L GA 45 32 16 5 0 0 2 0.93 0 1.15 2.7 3.1 1.53 2.39 11.7 96 O 788 1239 15 0.077 - O 1.54 EXAMPLE 48 "L" “GT 50 ^ 10 " 12 25 "0" 3 "0" 1.65 72 1.48 5.5 4.1 1.39 3.04 18.7 "82" ~ O ~ 1094 1350 8 0.046 - ~ O ~ 0.36 COMPARATIVE EXAMPLE 49 M GI 58 8 28 5 0 0 1 0.98 0 0.98 3.3 3.1 1.57 1.74 4.7 69 O 566 1031 20 0.125 - O 1.34 EXAMPLE 50 M GI 54 19 20 7 0 0 0 1.04 0 0.91 3.3 4.4 1.67 0.18 2.2 57 O 595 1053 19 0.121 - O 1.45 EXAMPLE 51 M GA 59 23 10 6 0 2 0 0.91 0 0.88 2.5 3.6 1.61 2.38 33.8 73 O 615 1215 15 0.089 - O 1.07 EXAMPLE 52 M GI 56 14 23 4 0 2 1 1.11 0 0.93 3.5 3.8 1.49 2.01 <1.0 756 O 725 1261 15 0.096 - X 1.08 COMPARATIVE EXAMPLE 53 N GI 57 18 15 7 0 1 2 1.19 0 1.20 3.4 2.0 1.26 0.80 35.5 41 O 688 1244 18 0.108O 1.41 EXAMPLE 5Γ "IT GA 65 "22" "8" ~~ 4 ~ "Ü" "1 "Ü" 1.00 —0 “ 1.08 3.4 2.1 0.74 7.00 87.2 "54" ~~ O ~ 481 967 22 0.138 - ~~ O ~ 1.21 EXAMPLE 55 N GA 51 25 16 50 3 1.05 0 0.86 2.7 2.9 1.31 2.47 24.3 72 O 704 1150 17 0.096 - O 1.04 EXAMPLE 56 N GI 63 18 13 4 0 2 0 1.26 0 0 97 4.7 2.4 0.80 1.87 58.1 53 O 624 1218 15 0.091 - O 0.46 COMPARATIVE EXAMPLE 57 O GI 66 10 17 3 0 1 3 1.01 0 1 05 3.0 3.5 1.66 0.74 43.9 37 O 473 1016 20 0.142 - O 1.16 EXAMPLE 58 O GI 63 4 8 0 23 2 0 1.00 5 1.04 3.1 4.2 1.61 3.12 260.3 46 O 1110 1404 12 0.083 - O 0.89 EXAMPLE 59 O GA 68 4 12 14 0 2 0 0.88 0 1.09 3.1 3.5 1.61 0.28 55.2 47 O 569 1203 16 0.104 - O 0.84 EXAMPLE 60 O GI 54 7 29 2 0 8 0 0.95 0 0.96 3.3 3.3 1.24 1.46 95.9 32 O 574 1000 22 0.147 - X 1.04 COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 108/134 [Table 17] I STOPPED PAGE 119 - DO NOT FORGET TO LOOK AT THE TERMS AND NOT ONLY THE NUMERICAL DATA.
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE BASE STEEL SHEET MICROESTRUT URA SURFACE LAYER (DECARBURIZED LAYER)BASE STEEL SHEET PROPERTY CLASSIFICATION STRUCTURAL FRACTION FERRITA STRUCTURE-TURARIGID RATIO OF RANDOM INTENSITY OF BCC IRON X-RAY INCLUSION DECARBURIZED LAYER THICKNESS DENSITY OFOXIDE10'2 OXIDES / m2 OXIDE SIZEç EXTERNAL APPEARANCE TRACTION PROPERTY RESISTANCE TO LATE FRACTURE FERRITA£ BAINITA BAINITIC FERRITA£ MARTENSITE£ TEMPERED MARTENSITE£ AUSTENITE WITHHELD£ OTHERS£ d (RD)/ d (TD) FERRITE FRACTION NOT RECRISTALIZED ° L (RD)/ L (TD) ASPECT PROPORTION D (RD) / D (TD) FLOW LIMITG5 CL 5 TENSION RESISTANCEG5 CL 5 TOTAL STRETCH£ VALUE NELECTRIC STRIPPINGDEPOSITION D D RESULTS OF THE CHLORIDE ACID IMMERSION TEST LIMIT DIFFUSIBLE HYDROGEN CONTENT 61Gl ^ 4- 26 ^ 6 Ί2 1.02 0 1.06 2.9 3.9 1.20 0 47 8.1 63 ^ O ^ 893 1407 12 0.068 -1.10 Example 62 P GA 45 35 15 3 0 1 1 1.03 0 0.98 3.0 2.2 1.43 5.18 23.8 86 O 771 1052 18 0.100 - O 1.39 Example 63 P GA 50 35 11 4 0 0 0 0.98 0 1.07 3.2 3.6 0.76 1.43 20.8 69 O 705 1166 16 0.098 - O 1.27 Example 64 "P" ~ GT "49" "25" 16 —4 ~ "0"~ 1 0.90 0 " 0.93 2.9 3.0 0.66 18.35 4.0 "292 "X" 530 889 20 0.114 - ~ O ~ 1.33 Comparative Example 65 Q Gl 73 0 18 6 0 3 0 1.03 0 0.93 3.3 2.2 0.75 2.22 144.4 48 O 479 1223 15 0.095 - O 1.01 Example 66 Q GA 69 12 5 14 0 0 0 0.82 0 1.12 3.3 2.9 1.21 5.71 234.9 49 O 518 1207 15 0.101 - O 0.98 Example 6 / "Q" GA 68 ~~ 6— 17 —R ~ "0" ~ Ύ ~ "0" 0.87 0 1.27 3.0 3.5 0.98 1.27 49.3 58 ~~ O ~ 504 1069 19 0.131 - ~~ O ~ 1.50 Example 68 Q Gl 92 0 0 0 0 0 8 0.92 0 1.02 3.2 3.2 1.37 1.06 43.2 59 O 658 778 8 0.052 - O 1.19 Comparative Example 69 R Gl 64 12 13 9 0 2 0 1.08 0 0.98 3.0 2.8 1.34 0 72 2.9 72 O 612 1146 17 0.106 - O 1 57 Example / 0 "R" GA 57 "26" ^ 10 " "6" "0" ~ 1 "0" 0.97 0 " 1.04 3.0 2.2 0.82 3.56 5.6 "Γ08 ~ O ~ 957 1126 15 0.085 - ~ O ~ 1.21 Example 71 R GA 60 22 13 5 0 0 0 0.96 4 0.91 3.0 3.1 1.54 4.17 5.1 113 O 619 1065 19 0.111 - O 1.12 Example 72 R Gl 60 10 22 6 0 0 2 1.07 0 1.19 3.1 2.4 1.16 14.42 8.9 104 O 620 1025 20 0.132 - O 0.85 Comparative Example / 3 s “GT 56 ^ T9 “ ^ 19 ” 5 "0" "1 "0" 1.11 0 1 07 3.0 3.4 1.29 0.84 16.1 58 ~~ O ~ 803 1135 17 0.096 - ~~ O ~ 1 65 Example 74 s GA 57 24 11 0 8 0 0 1.03 0 0.94 3.3 3.1 1.41 1 14 17.2 70 O 875 1117 17 0.105 - O 1 65 Example 75 s GA 57 22 10 9 0 2 0 1.12 0 1.01 2.4 3.0 1.51 4 63 24.1 91 O 802 1165 17 0.096 - O 0.85 Example
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Petition 870190028455, of March 25, 2019, p. 109/134 [Table 18]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE BASE STEEL SHEET MICRO-STRUCTURE SURFACE LAYER (DECARBURIZED LAYER)BASE STEEL SHEET PROPERTY CLASSIFICATION STRUCTURAL FRACTION FERRITA STRUCTURERIGID RATIO OF RANDOM INTENSITY OF BCC IRON X-RAY INCLUSION DECARBURIZED LAYER THICKNESSAND OXIDE DENSITY 10'2 OXIDES / m ² OXIDE SIZE _£ c EXTERNAL APPEARANCE TRACTION PROPERTY RESISTANCE TO LATE FRACTURE FERRITA£ BAINITA£ BAINITIC FERRITA£ MARTENSITE£ TEMPERED MARTENSITE£ AUSTENITE WITHHELD£ OTHERS£ d (RD)/ d (TD) Non-recrystallized ferrite fraction L (RD) / L (TD) ASPECT PROPORTION D (RD)/ D (TD FLOW LIMITCL5 Tensile strength csCL5 TOTAL STRETCH£ Value n ELECTRODEPOSITION STRIPPING RESULTS OF THE CHLORIDIC ACID IMMERSION TEST LIMIT DIFFUSIBLE HYDROGEN CONTENT 76 s GI 54 20 20 5 0 0 1 0.63 0 0.58 4.8 3.0 0.42 2.60 16.9 86 O 754 1053 8 0.044 - X 0.26 Comparative Example 77 T GI 45 14 28 10 0 3 0 0.96 0 0.95 3.1 3.9 1.50 1.21 13.7 66 O 814 1255 15 0.081 - O 1.30 Example 78 T GA 48 18 25 6 0 0 3 1.02 0 0.98 2.8 2.9 1.61 1.72 22.9 74 O 701 1265 16 0.085 - O 1.14 Example 79 T GA 51 19 20 8 0 1 1 0.95 0 0.90 2.6 3.4 1.68 0.64 29.2 56 O 713 1252 15 0.088 - O 1.55 Example 80 T Gl 48 16 26 8 0 2 0 1.02 0 0.93 3.0 5.5 2.3.7 4.45 43.6 71 O 779 1265 14 0.078 - O 2.44. Comparative Example 81 U Gl 77 0 16 7 0 0 0 0.94 0 1.01 3.4 4.0 1.43 1.93 7.5 89 O 369 936 23 0.170 - O 1.75 Example 82 U Gl 67 5 19 8 0 0 1 1.04 0 0.96 2.7 3.0 1.38 1.80 7.8 83 O 760 1043 16 0.103 - O 1.18 Example 83 U GA 58 12 20 8 0 2 0 1.01 0 0.83 3.1 3.1 1.25 1.59 7.6 82 O 661 1198 16 0.100 - O 1.08 Example 84 U Gl 70 0 23 6 0 1 0 1.39 0 1.40 4.2 4.4 1.61 1.09 5.7 83 O 443 1018 20 0.136 - O 0.40 Comparative Example 85 V Gl 65 9 18 8 0 0 0 1.05 0 1.05 3.5 3.7 1.42 1.91 19.1 78 O 497 1015 20 0.131 - O 1.36 Example 86 V Gl 68 10 14 7 0 1 0 0.98 0 0.97 3.0 3.7 1.59 0.78 13.4 73 O 439 1023 20 0.121 - O 1.40 Example 87 V GA 61 8 19 7 0 3 2 1.16 0 0.91 2.8 3.8 1.28 2.07 26.1 63 O 565 1066 19 0.120 - O 0.79 Example 88 V Gl 65 10 15 7 0 3 0 1.03 0 1.00 3.2 3.6 1.51 4.22 15.3 95 X 494 1005 21 0.149 - O 1.13 Comparative Example 89 W Gl 54 17 20 7 0 2 0 1.00 0 1.00 3.3 3.1 1.29 3.16 109.9 51 O 656 1166 16 0.093 - O 1.28 Example 90 W Gl 57 10 24 8 0 1 0 1.00 0 1.10 3.5 3.2 1.45 5.85 42.0 76 O 574 1042 19 0.120 - O 1.54 Example
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Petition 870190028455, of March 25, 2019, p. 110/134 [Table 19]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE BASE STEEL SHEET MICRO-STRUCTURE SURFACE LAYER (DECARBURIZED LAYER)BASE STEEL SHEET PROPERTY CLASSIFICATION STRUCTURAL FRACTION FERRITA RIGID STRUCTURE RATIO OF RANDOM INTENSITY OF BCC IRON X-RAY INCLUSION DECARBURIZED LAYER THICKNESS OXIDE DENSITY 10 ^lz OXIDES / m ^z OXIDE SIZEz EXTERNAL APPEARANCE TRACTION PROPERTY RESISTANCE TORE- FRACTURETARDY FERRITA£ BAINITA£ BAINITIC FERRITA£ MARTENSITE£ MARS NS ITA TE MP E RADA£ AUSTENITE WITHHELD£ OTHERS£ d (RD) / d (TD) FRACTION OF FERRITE NOT RECRISTALI- _the ZADA ° L (RD) / L (TD) ASPECT PROPORTION D (RD) / D (TD) FLOW LIMIT<CL5 TENSION RESISTANCE<CL5 TOTAL STRETCH£ VALUE N ELECTRODEPOSITION STRIPPING RESULTS OF THE CHLORIDIC ACID IMMERSION TEST PROPORTION OF HYDROGEN CONTENTDIFFUSIBLE LIMIT 91 W GA 65 11 5 14 0 2 3 1.03 0 0.96 2.6 3.4 1 69 0.89 85.9 34 O 564 1224 15 0.093 - O 1.36 EXAMPLE 92 W GI 83 0 5 3 0 0 9 0.90 0 1.05 3.3 3.5 1.39 1.92 141.1 50 O 474 850 16 0.123 - O 1.46 COMPARATIVE EXAMPLE IVO 93 X GI 55 17 20 7 0 1 0 1.29 23 1.31 2.7 3.5 1.49 1.33 11.2 89 O 847 1224 15 0.082 - O 1.14 EXAMPLE~ X ~ ~ GT "54" 21 ^ Γ3 “ 11 "0" 1 "0" 0.96 0 1.01 3.1 3.8 1.61 3.66 5.9 93 ~ O ~ 759 1134 17 0.094 - O 1.50 EXAMPLE 95 X GA 70 21 0 6 0 0 3 0.83 0 1.04 2.8 4.1 1.50 3.14 29.5 74 O 685 1144 17 0.107 - O 1.18 EXAMPLE 96 X GI 57 14 20 7 0 2 0 1.25 12 0.98 4.3 3.7 1.43 2.09 17.7 75 O 788 1132 17 0.104O 0.45 COMPARATIVE EXAMPLE 97 Y GI 57 10 22 8 0 1 2 1.01 0 1.04 3.2 3.3 1.27 1.45 7.1 55 O 671 1280 14 0.088 - O 1.17 EXAMPLE 98 Y GA 46 22 16 12 2 1 1 0.94 0 1.03 2.8 3.9 1.61 1.08 6.4 65 O 907 1425 12 0.070 - O 1.45 EXAMPLE 99 Y GA 48 19 20 12 0 0 1 1.07 0 1.05 2.7 3.4 1.37 2 42 10.8 62 O 710 1197 16 0.084 - O 1.13 EXAMPLE 100 Y GA 5I 5 30 8 0 3 3 0.92 0 1.02 2.9 3.9 1.70 1.59 58.2 57 O 706 1218 16 0.102 THERE ARECIA O 0.94 COMPARATIVE EXAMPLE 101 Z GI 63 0 7 23 0 4 3 1.01 0 1.04 2.6 2.5 1.36 3.23 21.9 83 O 523 1122 18 0.125 - O 0.64 EXAMPLE 102 Z GA 55 19 15 5 0 2 4 0.97 0 0.86 3.2 2.6 1.63 0.78 22.0 56 O 544 1000 21 0.140O 1.61 EXAMPLE 103 Z GA 55 13 27 4 0 0 1 1.04 0 0.91 3.1 3.2 1.29 0.86 25.2 60 O 570 1028 20 0.117 - O 0.97 EXAMPLE 104 Z GI 53 8 24 10 0 2 3 1.29 0 1.22 4.3 3.0 1.25 1.74 90.5 46 O 661 1151 17 0.109 - O 0.36 COMPARATIVE EXAMPLE 105 AA GI 52 7 30 9 0 2 0 1.08 0 1.12 3.2 2.8 1.35 3.88 88.7 60 O 808 1370 13 0.075 - O 1.16 EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 111/134 [Table 20]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE BASE STEEL SHEET MICRO-STRUCTURE SURFACE LAYER (DECARBURIZED LAYER)BASE STEEL SHEET PROPERTY CLASSIFICATION STRUCTURAL FRACTION FERRITA STRUCTURERIGID RATIO OF RANDOM INTENSITY OF BCC IRON X-RAY INCLUSION DECARBURIZED LAYER THICKNESS OXIDE DENSITY 10'2 OXIDES / m ² OXIDE SIZEç EXTERNAL APPEARANCE TRACTION PROPERTY RESISTANCE TORE- FRACTURETARDY FERRITA£ BAINITA£ BAINITIC FERRITA£ MARTENSITE£ TEMPERED MARTENSITE£ AUSTENITE WITHHELD£ OTHERS£ D (RD) / D (TD) FERRITE FRACTION NOT RECRISTALIZED ° L (RD)/ L (TD) ASPECT PROPORTION D (RD)/ D (TD) FLOW LIMITG5 CL 5 Tensile strength _M CL 5 TOTAL STRETCH VALUE N ELECTRODEPOSITION STRIPPING RESULTS OF THE CHLORIDE ACID IMMERSION TEST LIMIT DIFFUSIBLE HYDROGEN CONTENT 106 AA GI 48 11 28 11 0 0 2 0.85 0 0.81 2.9 3.8 0.85 5.95 166.9 47 O 634 1083 18 0.108 - O 0.79 Example 107 AA GA 56 13 20 9 0 1 1 0.97 0 1.26 2.8 2.8 0.67 3.73 73.9 61 0 696 1301 14 0.093 - O 1.27 Example 108 AA GI 57 3 33 7 0 0 0 1.00 0 1.05 3.1 2.9 1.24 3.78 41.5 82 O 591 1063 19 0.108 Existence O 0.70 Comparative Example 109 "AT “GT 64 11 15 -8 ^- "0" ~ 2 " "0 ^- 1.18 "0" 1.14 3.0 3.3 1.35 1.54 7.3 "88" O 616 1278 14 0.095 - O 1.05 Example 110 "AB GA "5 ^ 15 21 ~~ T ~ —0 " ~ 0 ” 3 1.13 ~ 0 ” 0.94 2.5 3.1 1.46 2.52 7.1 95 O 635 1132 17 0.098 - O 0.98 Example 111 AB GA 53 13 19 10 0 3 2 1.00 0 1.07 2.7 3.9 1.67 0.92 5.9 62 O 710 1214 16 0.102 - O 0.83 Example 112 AB GI 62 10 20 3 0 3 2 1.391.55 4.3 3.8 1.39 0.90 5.6 71 O 545 1039 20 0.140 - O 0.31 Comparative Example 113 "B.C “GT —48 ~ TT —18 “ —8 “ —0 " 1 3 1.01 ~ 0 ” 1.07 3.0 2.3 1.53 1.15 42.8 55 "O ^- 728 1162 16 0.087 - O 1.26 Example 114 B.C GA 54 34 0 9 0 0 3 1.10 0 0.98 2.9 2.5 1.37 1.34 35.6 54 O 673 1263 14 0.080 - O 1.46 Example 115 B.C GA 50 25 12 9 0 2 20 1.15 2.7 3.3 0.63 4.85 36.6 74 O 746 1197 16 0.093 - O 1.54 Example 116 B.C GI 49 16 19 14 0 0 2 1.30 0 1.08 4.8 1.9 1.17 0.81 18.8 62 O 704 1207 15 0.086 - O 0.37 Comparative Example 117 AD GI 47 8 340 2 2 1.02 0 1.00 3.0 2.6 0.78 1.37 65.3 55 O 954 1473 11 0.060 - O 1.58 Example 118 AD GA 46 23 20 8 0 0 3 0.89 0 1.07 2.8 2.5 1.23 1.99 154.4 42 O 791 1256 14 0.072 - O 0.72 Example 119 "AD GA ~ 44 ~ ~~ r ~ 11 32 "0" ~~ 4 ~1.00 0 " 1.18 2.7 2.7 0.95 1.00 40.3 53 O 919 14690.057 - O 1.02 Example 120 AD GI 51 11 30 6 0 1 -1 1.10 0 1.30 5.1 3.7 0.78 3.11 15.0 41 O 661 1156 17 0.091 _ O 0.42 Comparative Example
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Petition 870190028455, of March 25, 2019, p. 112/134 [Table 21]
EXPERIMENTAL EXAMPLE CHEMICAL COMPONENT STEEL TYPE BASE STEEL SHEET MICRO-STRUCTURE SURFACE LAYER (DECARBURIZED LAYER)BASE STEEL SHEET PROPERTY CLASSIFICATION STRUCTURAL FRACTION FERRITA STRUCTURERIGID RATIO OF RANDOM INTENSITY OF BCC IRON X-RAY INCLUSION DECARBURIZED LAYER THICKNESSAND OXIDE DENSITY 10 ^l2 OXIDES / m ^z OXIDE SIZEç EXTERNAL APPEARANCE TRACTION PROPERTY RESISTANCE TO LATE FRACTURE FERRITA£ BAINITA£ BAINITIC FERRITA£ MARTENSITE£ TEMPERED MARTENSITE£ AUSTENITE WITHHELD£ OTHERS£ D (RD) /(TD) FERRITE FRACTION NOT RECRISTALIZED L (RD) /L (TD) ASPECT PROPORTION D (RD)/ D (TD) FLOW LIMITG5 CL 5 Tensile strengthG5 CL 5 TOTAL STRETCH£ VALUE N ELECTRODEPOSITION STRIPPING RESULTS OF THE CHLORIDIC ACID IMMERSION TEST PROPORTION OF HYDROGEN CONTENTDIFFUSIBLE LIMITAE GI 66 ^ T2 ~ VZ 0.98 - 1.01 3.5 3.9 1.72 0.95 60.8 38482 767 22 0.132 - O 1.03 COMPARATIVE EXAMPLE 122 AF GI 22 18 30 23 0 7 0 0.90 0 1.00 2.0 3.9 1.42 2.43 43.8 64 O 1288 1642 10 0.065 - X 1.19 COMPARATIVE EXAMPLE 123 AG GI 88 8 2 0 0 2 0 0.97 0 0.97 3.9 2.8 1.45 0.53 5.7 89 O 368 629 20 0.158 - O 1.46 COMPARATIVE EXAMPLE 124 BA - TEST IN ’ rERROMPI DEVI OF A FRAT URA AT THE STEP OF LAMI NATION A COLD COMPARATIVE EXAMPLE 125 BB GA 63 15 5 14 1 0 2 1.03 0 1.08 3.4 3.5 1.68 0.83 <1.0 43 O 486 915 15 0.098 - X 1.40 COMPARATIVE EXAMPLE 126 BC - INTERRUPTED TEST DUE TO PLATE CRACKING COMPARATIVE EXAMPLE 127 "BD" - 1 ES 1 AND ERRUPTED INI DUE TO FRAI URA IN THE WELDING ZONE IN E 1 RECOZING APA 1 O COMPARATIVE EXAMPLE 128 BE GA 67 5 6 9 8 4 1 1.23 0 1.21 3.3 4.2 1.46 5.45 15000 37 O - - - - EXIS T IA - - COMPARATIVE EXAMPLE
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Petition 870190028455, of March 25, 2019, p. 113/134
105/113 [00186] As is evident from Table 13 to Table 21, in hot-dip galvanized steel sheets of the examples of the present invention, in which the chemical composition of the base steel sheet is in the range prescribed in the present invention and the microstructure The base steel sheet meets the conditions prescribed in the present invention and the thickness of the decarburized layer and the conditions of the oxides in the decarburized layer are in the ranges prescribed in the present invention, (Experimental examples 1 to 3, 5 to 7, 9 to 11, 13 to 15, 17 to 19, 21 to 23, 25 to 27, 29 to 31, 33 to 35, 37 to 39, 41 to 43, 45 to 47, 49 to 51, 53 to 55, 57 to 59, 61 to 63, 65 to 67, 69 to 71, 73 to 75, 77 to 79, 81 to 83, 85 to 87, 89 to 91, 93 to 95, 97 to 99, 101 to 103, 105 to 107, 109 to 111, 113 to 115 and 117 to 119), it was confirmed that the delayed fracture resistance assessed by the salt spray test is excellent, the anisotropy d the delayed fracture strength assessed by the proportion of the limit of the diffusible hydrogen contents in the respective directions is small and great resistance and high ductility are also provided and the n value is also high, the moldability is excellent and the quality of the external appearance it is good and the peel resistance of the electrodeposition layer is also good.
[00187] In contrast to this, in the comparative examples in which any one or more of the conditions deviated from the band / bands prescribed in the present invention, one or more of the respective performance performances described above were poor.
[00186] That is, Experimental Example 121 is a comparative example that uses the base steel plate that has a C content that is too small and in this case, the resistance was insufficient. Experimental Example 122 is a comparative example using the base steel sheet which has a very high C content and in this case, the delayed fracture strength has deteriorated. Experimental Example 123 is a comparative example using steel sheet ba
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106/113 if it has a content of Mn that is too small and in this case, the resistance was insufficient.
[00187] Experimental Example 124 is a comparative example that uses the base steel plate that has the Si content that is too large and is an example where the base steel plate fractured in the cold rolling step and the test was interrupted. Experimental Example 125 is a comparative example using the base steel sheet which has a Si content that is too small and in this case, the density of the oxides in the decarburized layer was small and the delayed fracture resistance deteriorated. Experimental Example 126 is a comparative example that uses the base steel plate that has the Mn content that is too large and is an example in which the fractured plate between completed the casting and that is subjected to a hot rolling stage and the test was interrupted. Experimental Example 127 is a comparative example that uses the base steel plate that has an Al content that is too large and is an example where in the continuous annealing step, an area welded to the previous fractured steel plate and the test was interrupted.
[00188] In relation to the comparative examples other than the Experimental Examples 121 to 127 described above, the chemical composition of the base steel plate was in the range prescribed in the present invention, however outside of the comparative examples, first, Experimental Example 4 is a comparative example in which the hot rolling condition was outside the range prescribed in Expression 1 (an example that exceeded the upper limit of Expression 1) and in this case, the proportion of inclusions in the base steel plate became large and thus the delayed fracture resistance deteriorated and the anisotropy of the delayed fracture resistance also became large.
Petition 870190028455, of March 25, 2019, p. 115/134
107/113 [00189] In addition, Experimental Example 8 is a comparative example in which the temperature of the treatment for formation of alloy in relation to the electrodeposition layer was too high and in this case, the resistance became insufficient and the resistance to peeling of the electrodeposition layer has deteriorated.
[00190] Experimental Example 12 is a comparative example in which the average cooling rate in the second cooling step in the cooling process of the base steel sheet annealing step was too low and in this case, the resistance became insufficient.
[00191] Experimental Example 16 is a comparative example in which, in the reduction zone of the annealing step, the value of the partial pressure P (H2O) / P (H2) of a partial pressure of water vapor P (H2O ) and a partial pressure of hydrogen P (H2) was too small and in this case, the decarburized layer did not form substantially and thus the delayed fracture resistance deteriorated and the external appearance became poor.
[00192] Experimental Example 20 is a comparative example in which the cooling rate of the primary cooling in the annealing stage of the base steel plate was too large and in this case, the resistance became insufficient.
[00193] Experimental Example 24 is a comparative example in which the cooling rate of the primary cooling in the hot rolling stage of the base steel plate was too large and in this case, the random proportion of the BCC iron intensity was large and the the degree of deflection of the crystal grains became large and thus the anisotropy of the delayed fracture resistance became large.
[00194] Experimental Example 28 is a comparative example in which the rate of increase in temperature of the annealing step of
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108/113 base steel plate was too large and in this case, the ratio of non-crystallized ferrite to ferrite was too large, so that a value of n became small and the moldability deteriorated.
[00195] Experimental Example 32 is a comparative example in which the average cooling rate of the steel sheet in the third cooling step after electrodeposition in the electrodeposition step was too small and in this case, the resistance became insufficient.
[00196] Experimental Example 36 is a comparative example in which the retention time in secondary cooling in the hot rolling stage of the base steel plate was too short and in this case, the hard island-shaped structures in the base steel plate they were extended in the lamination direction and thus the anisotropy and the delayed fracture strength became great.
[00197] Experimental Example 40 is a comparative example in which the temperature of interruption of the cooling of the primary cooling in the hot rolling stage of the base steel plate was too high and in this case, the external appearance became weak.
[00198] Experimental Example 44 is a comparative example in which the temperature increase rate of the base steel sheet annealing step was too high and in this case, it was found that the non-crystallized ferrite increases, the hard structures in the shape of the island has been transformed into extended shapes in the lamination direction and also the degree of deflection of the crystal also becomes large and in this way the anisotropy of the delayed fracture resistance becomes large, the value of n also becomes small and the moldability deteriorates [00199] Experimental Example 48 is a comparative example in which the reduction rate of cold rolling in the manufacturing process
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109/113 of the base steel plate was too low and in this case, it was found that the non-crystallized ferrite increases, the hard structures in the shape of an island have become extended shapes in the direction of the lamination and also the degree of deflection of the crystal becomes large and thus the anisotropy of the delayed fracture strength becomes large, the value of n also becomes small and the moldability deteriorates.
[00200] Experimental Example 52 is a comparative example in which the proportion of mixed gas in the preheating zone in the annealing stage of the base steel plate was too low and in this case, the oxides in the decarburized layer became coarse and at the same time , their density has become too small and thus the delayed fracture resistance has deteriorated.
[00201] Experimental Example 56 is a comparative example in which the waiting time (retention time) until the start of primary cooling after the hot rolling in the hot rolling stage of the base steel plate was completed was too short and in this case, the degree of deflection of the orientations of the crystal of the base steel plate became large and thus the anisotropy and the delayed fracture resistance also became large.
[00202] Experimental Example 60 is a comparative example in which the process of transformation of bainite (retention process) was carried out after hot galvanizing and in this case, the delayed fracture strength has deteriorated.
[00203] Experimental Example 64 is a comparative example in which the air ratio described above was too high and in this case, the thickness of the decarburized layer became too large and thus the insufficiency of the resistance was caused and a bad external appearance occurred .
Petition 870190028455, of March 25, 2019, p. 118/134
110/113 [00204] Experimental Example 68 is a comparative example in which the maximum heating temperature in the annealing stage of the base steel plate was too low and in this case, there was not enough reverse transformation to austenite and the ferrite remained excessively, so that resistance has become insufficient and moldability has also become weak.
[00205] Experimental Example 72 is a comparative example in which in the reduction zone of the base steel sheet annealing step, the value of the partial pressure ratio P (H2O) / P (H2) of a partial vapor pressure d 'water P (H2O) and a partial pressure of hydrogen P (H2) was too high and in this case, the decarburized layer was too thick, so it caused insufficient strength.
[00206] Experimental Example 76 is a comparative example in which the heating temperature of the plate at the time of manufacture of the base steel plate was too low and in this case, the anisotropy of the steel plate structure became large and thus the delayed fracture resistance has deteriorated, the anisotropy of delayed fracture resistance has also become large and yet the moldability has also become weak.
[00207] Experimental Example 80 is a comparative example in which the hot rolling condition of the base steel plate was outside the range prescribed in Expression 1 (an example in which it exceeded the upper limit of Expression 1) and in this case, the aspect ratio of inclusions in the base steel plate became large and thus the anisotropy of the delayed fracture strength became large.
[00208] Experimental Example 84 is a comparative example in which the retention time in secondary cooling in the hot rolling stage of the base steel plate was too short and
Petition 870190028455, of March 25, 2019, p. 119/134
111/113 in this case, the shapes of the island-like hard structures in the base steel plate were extended in the direction of the rolling and the degree of deflection of the entire steel plate structure also became large and thus the resistance anisotropy delayed fracture became large.
[00209] Experimental Example 88 is a comparative example in which the effective amount of Al from hot dip galvanizing was too much and in this case, a weak external appearance was caused.
[00210] Experimental Example 92 is a comparative example in which the cooling rate of the primary cooling of the base steel sheet annealing step was too small and in this case, the resistance became insufficient.
[00211] Experimental Example 96 is a comparative example in which the waiting time (retention time) until the start of the primary cooling after the hot rolling in the hot rolling stage of the base steel plate was completed was too short and in this case, the aspect ratio of inclusions in the base steel sheet has become large and thus the anisotropy of the delayed fracture strength has also become large.
[00212] Experimental Example 100 is a comparative example in which the time for the treatment of alloy formation after hot dip galvanizing was too long and in this case, the peeling resistance of the electrodeposition layer deteriorated.
[00213] Experimental Example 104 is a comparative example in which the hot rolling condition of the base steel plate was outside the range prescribed in Expression 1 (an example in which it was less than the lower limit value of Expression 1) and in this case, the degree of deflection of the structure of the base steel sheet became large and the anisotropy of the delayed fracture strength became large.
Petition 870190028455, of March 25, 2019, p. 120/134
112/113 [00214] Experimental Example 108 is a comparative example in which the effective amount of Al from hot dip galvanizing was too small and in this case, the peeling resistance of the electroplating layer became low.
[00215] Experimental Example 112 is a comparative example in which the cooling temperature of the primary cooling in the hot rolling stage of the base steel plate was too low and in this case, the degree of deflection of the steel plate structure it became large and the hard island-shaped structures were extended in the direction of the lamination and thus the anisotropy of the delayed fracture resistance became large.
[00216] Experimental Example 116 is a comparative example in which the hot rolling condition of the base steel plate was outside the range prescribed in Expression 1 (an example in which it was less than the lower limit value of Expression 1) and in this case, the degree of deflection of the steel sheet structure became large and thus the anisotropy of the delayed fracture strength became large.
[00217] In Experimental Example 120, the rate of reduction of cold rolling in the base steel sheet manufacturing process was too large and the degree of deflection of the steel sheet structure became large and thus the anisotropy of the delayed resistance the fracture also became big.
[00218] Experimental Example 128 is an example in which the proportion of air previously described in the oxidation treatment zone was too large and thus the density of oxides in the decarburized layer became excessively high and the electrodeposition adhesion deteriorated extremely and thus, the traction test and the delayed fracture resistance assessment test were interrupted.
Petition 870190028455, of March 25, 2019, p. 121/134
113/113
INDUSTRIAL APPLICABILITY [00219] The present invention can be applied appropriately to parts that have been subjected to hot dip galvanizing and that have been subjected to work such as bending and also to be used in fields where a large load is added between the parts in which is necessary to have a resistance such as for structural parts and reinforcement parts for automobiles, construction machines etc., for example, and can be applied to parts in which the occurrence of delayed fracture, in particular, had to be avoided. However, the forms of application of the present invention are not limited to these.

权利要求:
Claims (11)
[1]
1. Hot-dip galvanized steel sheet, characterized by the fact that it comprises:
a base steel plate made of steel consisting of:
% in large scale,
C: 0.075 to 0.400%;
Si: 0.01 to 2.00%;
Mn: 0.80 to 3.50%;
P: 0.0001 to 0.100%;
S: 0.0001 to 0.0100%;
Al: 0.001 to 2.00%;
O: 0.0001 to 0.0100%;
N: 0.0001 to 0.0100%; and optionally,% by mass, one species or two or more species selected from among
Cr: 0.01 to 2.00%,
Ni: 0.01 to 2.00%,
Cu: 0.01 to 2.00%,
Mo: 0.01 to 2.00%,
B: 0.0001 to 0.0100%,
W: 0.01 to 2.00%,
Ti: 0.001 to 0.150%,
Nb: 0.001 to 0.100%,
V: 0.001 to 0.300%,
0.0001 to 0.0100% by weight in the total of one species or two or more species selected from Ca, Ce, Mg, Zr, La and REM, and the rest being composed of Fe and unavoidable impurities; and a hot dip galvanizing layer formed on top
Petition 870190028455, of March 25, 2019, p. 123/134
[2]
2/7 surface of said base steel plate, where in a range of 1/8 thickness to 3/8 thickness with the position of 1/4 thickness of the plate thickness of said base steel plate of the surface of said base steel plate being the center, the structure of said base steel plate is transformed into a structure in which
40 to 90% by volume fraction of a ferrite phase is contained, the retained austenite phase is 5% or less by volume fraction, new martensite is 0 (zero) to 40% by volume fraction, tempered martensite is 0 (zero) to 50% by volume fraction, bainitic and / or bainite ferrite is 0 (zero) to 60% by volume fraction, pearlite and / or coarse cementite is from 0 (zero) to 6% in volume fraction , and yet the proportion of non-crystallized ferrite for the whole ferrite phase is 50% or less in fraction of volume, a proportion of diameter of the grain of crystal grains in the ferrite phase in said base steel plate is 0, 75 to 1.33, wherein said proportion of grain diameter is defined as the proportion of an average grain diameter in the lamination direction divided by an average grain diameter in the direction of the plate width of said phase, and a proportion length of the hard structures dispersed in island formats in the ferrite phase is 0.75 to 1.3 3, wherein said length ratio is defined as an average length in the lamination direction divided by an average length in the direction of the plate width of said structures, and also an average aspect ratio of inclusions contained in said base steel plate it's from
Petition 870190028455, of March 25, 2019, p. 124/134
[3]
3/7
1.0 to 5.0, and a superficial layer of said base steel plate is transformed into the decarburized layer that has a thickness of 0.01 to 10.0 pm, and also an average diameter of the oxide grain in the decarburized layer is from 30 to 500 nm, and an average density of oxides in the decarburized layer is in the range of 1.0 χ 10 ¹² oxides / m ² to 1.0 χ 10 ¹⁶ oxides / m ² .
2. Hot-dip galvanized steel sheet, according to claim 1, characterized by the fact that the said base steel sheet still consists of,% by mass, one species or two or more species selected among
Cr: 0.01 to 2.00%,
Ni: 0.01 to 2.00%,
Cu: 0.01 to 2.00%,
Mo: 0.01 to 2.00%,
B: 0.0001 to 0.0100%, and
W: 0.01 to 2.00%.
3. Hot-dip galvanized steel sheet, according to claim 1, characterized by the fact that the said base steel sheet still consists of,% by mass, one species or two or more species selected among
Ti: 0.001 to 0.150%,
Nb: 0.001 to 0.100%, and
V: 0.001 to 0.300%.
[4]
4. Hot-dip galvanized steel sheet, according to claim 1, characterized by the fact that said base steel sheet still consists of 0.0001 to 0.0100% by weight in the total of one species or two or more species selected from Ca, Ce, Mg, Zr, La and REM.
[5]
5. Hot-dip galvanized steel sheet, according to
Petition 870190028455, of March 25, 2019, p. 125/134
4/7 claim 1, characterized by the fact that, in said base steel plate, an average hardening coefficient per work (value of n) in a range where the total elongation is 3 to 7% is 0.060 or more.
[6]
6. Hot-dip galvanized steel sheet, according to claim 1, characterized by the fact that, in said base steel sheet, a value of a diffusible hydrogen content at the limit in the direction of the lamination divided by a diffusible hydrogen content at the limit in the direction of the plate width is in the range of 0.5 to 1.5.
[7]
7. Hot-dip galvanized steel sheet, according to claim 1, characterized by the fact that, in said base steel sheet, a proportion of random intensity of X-rays of BCC iron in the position of 1/4 of a thickness of a surface is 4.0 or less.
[8]
8. Hot-dip galvanized steel sheet according to claim 1, characterized by the fact that said hot-dip galvanizing layer is an alloy layer.
[9]
9. Hot-dip galvanized steel sheet manufacturing process, characterized by the fact that it comprises:
a hot rolling step in which the plate consisting of:
% in large scale,
C: 0.075 to 0.400%;
Si: 0.01 to 2.00%;
Mn: 0.80 to 3.50%;
P: 0.0001 to 0.100%;
S: 0.0001 to 0.0100%;
Al: 0.001 to 2.00%;
O: 0.0001 to 0.0100%;
N: 0.0001 to 0.0100%, optionally,% by mass, one species or two or
Petition 870190028455, of March 25, 2019, p. 126/134
5/7 more species selected among
Cr: 0.01 to 2.00%,
Ni: 0.01 to 2.00%,
Cu: 0.01 to 2.00%,
Mo: 0.01 to 2.00%,
B: 0.0001 to 0.0100%,
W: 0.01 to 2.00%,
Ti: 0.001 to 0.150%,
Nb: 0.001 to 0.100%,
V: 0.001 to 0.300%,
0.0001 to 0.0100% by weight in total of one species or two or more species selected from Ca, Ce, Mg, Zr, La and REM, and the remainder consisting of Fe and unavoidable impurities, is heated to 1080 ° C or more, hot rolling is started, the total number of passes (-) from the start of the hot rolling to the hot finishing rolling is set to N, a rolling temperature (° C) on the umpteenth pass is adjusted to TPi and a reduction ratio (-) on the nth pass is adjusted to laugh, hot rolling is performed in such a way that N, TPi er satisfy Expression A below, and hot rolling is finished when the temperature of a base steel plate is a temperature in the range of 850 to 980 ° C;
a primary cooling step in which a period of time from the hot finish rolling to the start of cooling is set to 1.0 seconds or more, the hot rolled base steel sheet is mainly cooled at a cooling rate not less than 5 ° C / s or more than 50 ° C / s, and primary cooling is interrupted when the plate temperature
Petition 870190028455, of March 25, 2019, p. 127/134
6/7 of base steel is a temperature in the range of 500 to 650 ° C;
subsequent to said primary cooling step, a secondary cooling step in which the base steel plate is cooled slowly in such a way that a period of time has elapsed before the temperature of the base steel plate becomes 400 ° C from the temperature at the time of the primary cooling which is interrupted it becomes an hour or more, and is cooled secondarily;
after secondary cooling, a cold rolling stage of the base steel plate by adjusting the total reduction ratio to 30 to 75%;
after cold rolling, an annealing step in which the temperature is increased in such a way that an increasing average temperature rate in the range of 600 to 750 ° C becomes 20 ° C / s or less, the steel sheet cold rolled base is heated to a temperature of 750 ° C or more, and subsequently the heated base steel sheet is cooled in such a way that an average cooling rate in the range of 750 to 650 ° C becomes 1.0 at 15.0 ° C / second; and the electroplating step of performing hot galvanization on the surface of the base steel plate obtained after said annealing step.
[Numeric expression 1]
0.10 5 £ 1.00x 10 ⁰ x exp- i = l
2.44 xIG ⁴ (7 ^ + 273)
(] 543-πΓ) ^ ^100χ10 ~ ³ pages · (Expression A)
[10]
10. Hot-dip galvanized steel sheet manufacturing process, according to claim 9, characterized by the fact that said annealing step and said electrodeposition step are carried out continuously by continuous annealing and
Petition 870190028455, of March 25, 2019, p. 128/134
7/7 electrodeposition line that has a preheat zone, a reduction zone and an electrodeposition zone, plus at least part of the preheat zone is adjusted to an oxidation treatment zone in which a proportion of air that is a value of the volume of air contained in a mixed gas per volume unit, being a mixed air gas used for a burner for heating gas combustion, divided by the volume of air theoretically necessary to cause complete combustion of the flue gas contained in the gas mixed per volume unit is 0.7 to 1.2, and in the oxidation treatment zone, oxides are generated in a part of the base layer of the base steel plate obtained after cold rolling, and then in the zone reduction ratio in which a partial pressure ratio P (H2O) / P (H2), which is a value of a partial pressure of water vapor divided by a partial pressure of hydrogen, is 0.0001 to 2.0, oxides are reduced, and en Therefore, the electrodeposition zone, the base steel plate that passed through the reduction zone is immersed in a hot dip galvanizing bath with an electrodeposition bath temperature set at 450 to 470 ° C and an effective amount of Al in the bath. electrodeposition adjusted to 0.01 to 0.18% by mass, with the proviso that the temperature of the steel plate at the time of the entry of the electrodeposition bath is from 430 to 490 ° C, and thus the hot galvanization is carried out on the surface of the base steel plate.
[11]
11. Process for the manufacture of a hot-dip galvanized steel sheet, according to claim 9, characterized by the fact that it also comprises:
after said electroplating step, an alloy forming treatment step to form a hot dip galvanizing alloy layer.

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法律状态:
2018-07-10| B06A| Notification to applicant to reply to the report for non-patentability or inadequacy of the application [chapter 6.1 patent gazette]|

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2018-12-26| B07A| Technical examination (opinion): publication of technical examination (opinion) [chapter 7.1 patent gazette]|

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2019-08-20| B25D| Requested change of name of applicant approved|Owner name: NIPPON STEEL CORPORATION (JP) |

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2019-11-05| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2019-12-31| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 28/09/2012, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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JP2011218776|2011-09-30|

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PCT/JP2012/075108|WO2013047760A1|2011-09-30|2012-09-28|High-strength hot-dip galvanized steel sheet having excellent delayed fracture resistance, and method for producing same|

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