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    • 专利摘要:
    hot rolled steel sheet, cold rolled steel sheet, galvanized steel sheet and production method thereof. a hot-rolled steel plate has an average value of the orientation group x-ray random intensity ratio {100}? to {223} <110> at least in a central portion of the plate thickness, ie , in a plate thickness range of 5/8 to 3/8 from the plate surface of 1.0 to 6.0, a crystal orientation x-ray random intensity ratio {332} <113> from 1.0 to 5.0, r ~ c ~ which is the value r in the direction perpendicular to the rolling direction from 0.70 to 1.10, and r ~ 30 ~ which is the value r in a direction that forms an angle of 30 <198> relative to the rolling direction from 0.70 to 1.10
    公开号:BR112013001864B1
    申请号:R112013001864-0
    申请日:2011-07-27
    公开日:2019-07-02
    发明作者:Nobuhiro Fujita；Kunio Hayashi；Riki Okamoto；Manabu Takahashi；Tetsuo Kishimoto；Hiroshi Yoshida
    申请人:Nippon Steel & Sumitomo Metal Corporation；
    IPC主号:
    专利说明:

    Descriptive Report of the Invention Patent for HOT LAMINATED STEEL SHEET, COLD LAMINATED STEEL SHEET, GALVANIZED STEEL SHEET AND METHODS OF PRODUCTION OF THE SAME.
    TECHNICAL FIELD [001] The present invention relates to a hot rolled steel sheet, a cold rolled steel sheet, and a galvanized steel sheet which are excellent in terms of local deformation capacity, such as bending, flanging by stretching, or deburring work, has a small dependence on forming ability orientation, and is used mainly for automobile components and the like, and methods for producing them. The hot rolled steel sheet includes hot rolled strips that serve as a starting plate for cold rolled steel sheet, galvanized steel sheet, or the like.
    [002] Priority is claimed on Japanese Patent Application No. 2010-169670, registered on July 28, 2010, Japanese Patent Application No. 2010-169627, registered on July 28, 2010, Japanese Patent Application No. 2011 -048236, registered on March 4, 2011, Japanese Patent Application No. 2010-169230, registered on July 28, 2010, Japanese Patent Application No. 2011-048272, registered on March 4, 2011, Patent Application Japanese Patent No. 2010-204671, filed on September 13, 2010, Japanese Patent Application No. 2011-048246, filed on March 4, 2011, and Japanese Patent Application No. 2011-048253, filed on 4 de m arc 2011, whose contents are incorporated here as a reference. BACKGROUND OF THE TECHNIQUE [003] An attempt is being made to reduce the weight of an automobile structure by using a high-strength steel plate to suppress the amount of carbon dioxide expelled
    Petition 870190036901, of 4/17/2019, p. 4/170
    2/121 for a car. In addition, a high-strength steel plate as well as a mild steel plate has often been used for automobile structures from the point of view of ensuring passenger safety. However, in order to also reduce the weight of an automobile structure in the future, it is necessary to increase the level of operational strength of a high-strength steel plate compared to the relative technique.
    [004] However, in general, an increase in the strength of a steel sheet results in a decrease in the forming capacity. For example, Non-Patent Document 1 describes that an increase in strength degrades the uniform elongation that is important for drawing or drawing by stretching.
    [005] Therefore, in order to use a high-strength steel plate for inferior components of the structure of an automobile, components that contribute to the absorption of impact energy, and the like, it is important to improve the local deformation capacity, such as ductility location that contributes to forming capacity such as deburring work capacity or folding work capacity.
    [006] In contrast to the above, Non-Patent Document 2 describes a method in which uniform elongation is improved by the complexity of the metal structure, even when the strength is maintained at the same level.
    [007] In addition, Non-Patent Document 3 describes a method of controlling the metal structure in which the local deformation capacity represented by the bending properties, hole expansion work capacity, or deburring work capacity is improved through control of inclusions, formation of a single structure and, in addition, a decrease in the difference in hardness between the structures. The above method is to improve the PROPetition 870190036901, of 17/04/2019, p. 5/170
    3/121 bore expansion properties by the formation of a single structure through the control of the structure and, to form a single structure, a heat treatment from a single austenite phase serves as the basis of the production method as described in the Document of no Patent 4.
    [008] In addition, Non-Patent Document 4 describes a technique in which a metal structure is controlled by controlling the cooling after hot rolling, and deformed precipitates and structures are controlled in order to obtain ferrite and bainite in one adequate proportion, thereby satisfying both an increase in strength and a guarantee of ductility.
    [009] However, all of the above techniques are a method of improving local deformation capacity by controlling the structure which is significantly influenced by the formation of the base structure.
    [0010] Meanwhile, even for improving the quality of the material through an increase in rolling reduction in a continuous hot rolling process, the relative technique exists, which is the so-called grain refining technique. For example, Non-Patent Document 5 describes a technique in which a large reduction is performed over an extremely low temperature range over an austenite range, and the non-recrystallized austenite is transformed into ferrite so that the ferrite crystal grains which is the main phase of the product are refined, and the strength or toughness increases due to the refining of the grain. However, Non-Patent Document 5 does not pay attention to the improvement of local deformation capacity, which is the objective of the present invention.
    LIST OF QUOTES
    NON-PATENT DOCUMENTS [0011] [Non-Patent Document 1] Nippon Steel Corporation
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    4/121
    Technical Report, Kishida (1999) No. 371, pg. 13 [0012] [Non-Patent Document 2] Trans. ISIJ, O. Matsumura et al. (1987) Vol. 27, pg. 570 [0013] [Non-Patent Document 3] Steel-manufacturing studies, Kato et al. (1984) Vol. 312, pg. 41 [0014] [Non-Patent Document 4] ISIJ International, K. Sugimoto et al. (2000) Vol.40, pg. 920 [0015] [Non-Patent Document 5] NFG Catalog, Nakayama Steel Works, Ltd.
    SUMMARY OF THE INVENTION
    TECHNICAL PROBLEM [0016] As described above, the control of the structure including the control of inclusions was the main solution to improve the local deformation capacity of a high-strength steel plate. However, since the solution has control of the structure, it was necessary to control the proportion or shape of the structures, such as ferrite and bainite, and the metal structure of the base was limited.
    [0017] Therefore, in the present invention, texture control is used instead of base structure control, and a hot-rolled steel plate, a cold-rolled steel plate, and a galvanized steel plate that are excellent in terms of the local deformation capacity of a high-strength steel plate, and have a small dependence on the orientation of the forming capacity, and a method of producing them is provided by controlling the size or shape of the crystal grains and the texture as well as the types of phases.
    SOLUTION TO THE PROBLEM [0018] According to the knowledge of the relative technique, the properties of hole expansion, bending properties, and the like have been improved by controlling inclusions, refining the
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    5/121 precipitation, homogenization of the structure, formation of a single structure, reduction of the difference in hardness between the structures and the like. However, with only the techniques above, the composition of the main structure will be limited. In addition, in a case where Nb, Ti and the like, which are typical elements that want to contribute significantly to the increase in resistance, are added to increase resistance, since there is a concern that anisotropy may increase greatly, it is necessary sacrifice other conformation factors or limit the direction in which the spans are taken prior to conformation, thus limiting the uses.
    [0019] Therefore, the present inventors recently paid attention to the influence of texture on a steel plate to improve bore expansion properties or the ability to bend work and studied and investigated the effects in detail. As a result, the inventors clarified that the local deformation capacity is drastically improved by controlling the random X-ray intensity of the respective orientations of a group of crystal orientations specific to a hot lamination process and, in addition, controlling the r value in the lamination direction, the r value in the direction perpendicular to the lamination direction, and the r value in a direction that forms an angle of 30 ° or 60 ° with respect to the lamination direction.
    [0020] The present invention was constituted on the basis of the above discovery, and the present invention employed the following measures to solve the above problems and achieve the relevant objective.
    (1) That is, a hot rolled steel sheet according to one aspect of the present invention contains, in mass%, C: 0.0001% to 0.40%, Si: 0.001% to 2.5%, Mn: 0.001% to 4.0%, P: 0.001% to 0.15%, S: 0.0005% to 0.03%, Al: 0.001% to 2.0%, N: 0.0005% to 0.01 %, and O: 0.0005% to 0.01%, and also contains one or two or more
    Petition 870190036901, of 4/17/2019, p. 8/170
    6/121 elements between Ti: 0.001% to 0.20%, Nb: 0.001% to 0.20%, V: 0.001% to 1.0%, W: 0.001% to 1.0%, B: 0.0001 % to 0.0050%, Mo: 0.001% to 1.0%, Cr: 0.001% to 2.0%, Cu: 0.001% to 2.0%, Ni: 0.001% to 2.0%, Co: 0 , 0001% to 1.0%, Sn: 0.0001% to 0.2%, Zr: 0.0001% to 0.2%, As: 0.0001% to 0.50%, Mg: 0.0001 % to 0.010%, Ca: 0.0001% to 0.010%, and rare earths: 0.0001% to 0.1% and the balance composed of iron and the inevitable impurities, in which the average value of the random intensity ratio of X-rays of a group of orientations {100} <011> to {223} <110> at least in a central portion of the thickness that is in the range of plate thickness from 5/8 to 3/8 from the plate surface steel is 1.0 to 6.0, the random X-ray intensity ratio of a {332} <113> crystal orientation is 1.0 to 5.0, rC which is the r value in the direction perpendicular to the direction lamination is 0.70 to 1.10, and r30 which is the r value in a direction that forms an angle of 30 ° to the lamination direction is 0, 70 to 1.10.
    (2) In addition, in the aspect according to item (1) above, in addition, rL which is the r value in the rolling direction can be 0.70 to 1.10, and r60 which is the r value in the forming direction. an angle of 60 ° in relation to the rolling direction can be 0.70 to 1.10.
    (3) In addition, in the aspect according to item (1) or (2) above, in addition, one or two or more between bainite, martensite, perlite and austenite are present in the hot-rolled steel plate, and the proportion of grains having dL / dt, which is the ratio of the length in the lamination direction dL to the length in the direction of the sheet thickness dt of 3.0 or less in the crystal grains in the structures can be 50% to 100%.
    (4) In the aspect according to item (1) or (2) above, the proportion of area of the crystal grains that have a grain diameter of more than 20 gm in a total area of a metallic structure in the rolled steel sheet a hot can be 0% to 10%.
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    7/121 (5) A cold rolled steel sheet according to one aspect of the present invention is a cold rolled steel sheet obtained by cold rolling the hot rolled steel sheet according to item (1) above, in which the mean value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> at least in the central portion of the thickness is 1.0 to less than 4.0, the ratio of random X-ray intensity of a {332} <113> crystal orientation is 1.0 to 5.0, rC which is the r value in a direction perpendicular to the lamination direction is 0.70 to 1.10, and r30 which is the r-value in a direction that forms an angle of 30 ° with respect to the rolling direction is 0.70 to 1.10.
    (6) In the aspect according to item (5) above, rL which is the value r in the rolling direction can be from 0.70 to 1.10, and r60 which is the value r in a direction that forms an angle of 60 ° in relation to the rolling direction it can be 0.70 to 1.10.
    (7) In the aspect according to item (5) or (6) above, also one or two or more between bainite, martensite, perlite and austenite are present in the cold rolled steel sheet, and the proportion of grains that have dL / dt which is the ratio of the length in the lamination direction dL to the length in the direction of the sheet thickness dt of 3.0 or less in the crystal grains in the structures can be 50% to 100%.
    (8) In the aspect according to item (5) or (6) above, the area ratio of the crystal grains that have a grain diameter of more than 20 pm in a total area of the metal structure in the cold rolled steel sheet it can be 0% to 10%.
    (9) The galvanized steel sheet according to one aspect of the present invention is a galvanized steel sheet also having a galvanized coating layer or a galvanized and annealed coating layer on a surface of the cold rolled steel sheet as per item (5 ) above, in which the average
    Petition 870190036901, of 4/17/2019, p. 10/170
    8/121 random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> at least in the central portion of the thickness is 1.0 to less than 4.0, the intensity ratio X-ray randomization of a {332} <113> crystal orientation is 1.0 to 5.0, rC which is the r value in a direction perpendicular to the lamination direction is 0.70 to 1.10, and r30 which the value r in a direction that forms an angle of 30 ° in relation to the rolling direction is 0.70 to 1.10.
    (10) In the aspect according to item (9) above, rL which is the Value r in the rolling direction can be 0.70 to 1.10, and r60 which is the value r in the direction that forms an angle of 60 ° in the rolling direction can be 0.70 to 1.10.
    (11) In a method of producing hot-rolled steel sheet according to one aspect of the present invention, initially a hot rolling mill in which an ingot or plate containing, in mass%, C: 0.0001% to 0, 40%, Si: 0.001% to 2.5%, Mn: 0.001% to 4.0%, P: 0.001% to 0.15%, S: 0.0005% to 0.03%, Al: 0.001% to 2.0%, N: 0.0005% to 0.01%, and O: 0.0005% to 0.01%, and also contains one or two or more elements between Ti: 0.001% to 0.20%, Nb: 0.001% to 0.20%, V: 0.001% to 1.0%, W: 0.001% to 1.0%, B: 0.0001% to 0.0050%, Mo: 0.001% to 1.0 %, Cr: 0.001% to 2.0%, Cu: 0.001% to 2.0%, Ni: 0.001% to 2.0%, Co: 0.0001% to 1.0%, Sn: 0.0001% 0.2%, Zr: 0.0001% to 0.2%, As: 0.0001% to 0.50%, Mg: 0.0001% to 0.010%, Ca: 0.0001% to 0.010%, and rare earths: 0.0001% to 0.1% and the balance being composed of iron and the inevitable impurities is laminated at least once at a lamination reduction ratio of 20% or more is performed over a temperature range of 1000 ° C to 1200 ° C, the austenite grain diameter is adjusted at 200 pm or less, a second hot lamination in which the total lamination reduction ratio is 50% or more is performed in a temperature range from T1 + 30 ° C to T1 + 200 ° C, a third lamination hot in which the
    Petition 870190036901, of 4/17/2019, p. 11/170
    9/121 total lamination reduction ratios less than 30% are performed in a temperature range from T1 ° C to T1 + 30 ° C, and hot rolling ends at a transformation temperature Ar3 or higher. [0021] Here, T1 is the temperature determined by the steel plate components and expressed by the formula1 below.
    T1 (° C) = 850 + 10 x (C + N) x Mn + 350 x Nb + 250 x Ti + 40 x B + 10 x Cr + 100 x Mo + 100 x V ··· (Formula 1) (12 ) As per item (11) above, in the second hot rolling in the temperature range from T1 + 30 ° C to
    T1 + 200 ° C, the ingot or plate can be laminated at least once at a lamination reduction rate of 30% or more in one pass.
    (13) In the aspect according to item (11) or (12) above, in the first hot rolling in a temperature range of 1000 ° C to 1200 ° C, the ingot or plate can be laminated at least twice at one lamination reduction ratio of 20% or more, and the diameter of the austenite grain can be adjusted to 100 gm or less.
    (14) In the aspect according to item (11) or (12) above, in a case where the pass in which the lamination reduction ratio is 30% or more in the temperature range from T1 + 30 ° C to T1 + 200 ° C is defined as a large reduction pass, the waiting time t from the end of the final pass of the large reduction pass to the start of cooling can employ a configuration that satisfies formula 2 below.
    t1 <t <t1 x 2.5 (Formula 2) [0022] Here, t1 is expressed by formula 3 below.
    t1 = 0.001 x ((Tf - T1) x P1) 2 - 0.109 x ((Tf - T1) x P1) + 3.1 (Formula 3) [0023] Here, Tf represents the temperature after the final pass, and P1 represents the ratio of lamination reduction in the final pass.
    (15) In the aspect according to item (14) above, the temperature
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    10/121 of the steel sheet can increase by 18 ° C or less between the respective passes of the second hot rolling in the temperature range from T1 + 30 ° C to T1 + 200 ° C.
    (16) In a method of producing cold rolled steel sheet according to an aspect of the present invention, after the end of hot rolling at transformation temperature Ar3 or higher, the hot rolled steel sheet obtained using the production method the hot-rolled steel sheet according to item (11) is pickled, cold rolled at 20% to 90%, annealed at a temperature in the range of 720 ° C to 900 ° C for a retention time of 1 second at 300 seconds, cooled rapidly at a cooling rate of 10 ° C / s to 200 ° C / s from 650 ° C to 500 ° C, and maintained at a temperature of 200 ° C to 500 ° C.
    (17) In the aspect according to item (16) above, in the second hot rolling in the temperature range of T1 + 30 ° C to T1 + 200 ° C, rolling at a rolling rate of 30% or more in one pass can be performed at least once.
    (18) In the aspect according to item (16) or (17) above, in the first hot rolling in the temperature range of 1000 ° C to 1200 ° C, lamination at a lamination ratio of 20% or more can be performed at least twice, and the austenite grain diameter can be adjusted to 100 pm or less.
    (19) In the aspect according to item (16) or (17) above, in a case where the pass in which the lamination reduction ratio is 30% or more in the temperature range from T1 + 30 ° C to T1 + 200 ° C is defined as a large reduction pass, the waiting time t from the end of the final pass of the large reduction pass to the start of cooling can employ a configuration that satisfies formula 4 below.
    t1 <t <t1 x 2.5 ··· (Formula 4)
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    11/121 [0024] Here, t1 is expressed by formula 5 below.
    t1 = 0.001 X ((Tf - T1) X P1) 2 - 0.109 x ((Tf - T1) x P1) + 3.1 (Formula 5) [0025] Here, Tf represents the temperature after the final pass, and P1 represents the ratio of lamination reduction in the final pass.
    (20) In the aspect according to item (16) or (17) above, the temperature of the steel sheet can increase by 18 ° C or less between the respective passes of the second hot rolling in the temperature range of T 1 + 30 ° C to T1 + 200 ° C.
    (21) In a method of producing galvanized steel sheet in accordance with one aspect of the present invention, after the end of hot rolling at transformation temperature Ar3 or higher, the hot rolled steel sheet obtained using the sheet production method hot rolled steel according to item (11) above is rolled in a temperature range of 680 ° C at room temperature, pickled, cold rolled at 20% to 90%, heated to a temperature range of 650 ° C to 900 ° C, annealed for a retention time of 1 second to 300 seconds, cooled at a cooling rate of 0.1 ° C / s to 100 ° C / s from 720 ° C to 580 ° C, and the galvanizing treatment runs.
    (22) In the aspect according to item (21) above, in the second hot rolling in the temperature range from T1 + 30 ° C to T1 + 200 ° C, lamination at a reduction rate of 30% or more in one pass can be performed at least once.
    (23) In the aspect according to item (21) or (22) above, in the first hot rolling in the temperature range of 1000 ° C to 1200 ° C, a lamination at a lamination reduction ratio of 20% or more can be performed at least twice, and the diameter of the austenite grain can be adjusted to 100 qm or less.
    (24) In the aspect according to item (21) or (22) above, in a case where the pass in which the lamination reduction is 30% or more
    Petition 870190036901, of 4/17/2019, p. 14/170
    12/121 in the temperature range T1 + 30 ° C to T1 + 200 ° C is defined as the large reduction pass, the waiting time t from the end of the final pass of the large reduction pass until the start of cooling can employ a configuration that satisfies formula 6 below.
    t1 <t <t1 x 2.5 ··· (Formula 6) [0026] Here, t1 is expressed by the following formula 7.
    t1 = 0.001 x ((Tf - T1) x P1) 2 - 0.109 x ((Tf - T1) x P1) + 3.1 ··· (Formula 7) [0027] Here, T represents the temperature after the final pass and P1 represents the lamination reduction ratio in the final pass.
    (25) In the aspect according to the item, (24) above, the temperature of the steel plate can increase by 18 ° C or less between the respective passes of the second hot rolling in the temperature range of T1 + 30 ° C to T1 + 200 ° C.
    ADVANTAGE EFFECTS OF THE INVENTION [0028] According to the present invention, without limiting the components of the main structure, it is possible to obtain a hot-rolled steel sheet, a cold-rolled steel sheet, and a galvanized steel sheet having a small influence on anisotropy even when elements such as Nb or Ti are added, are excellent in terms of local deformation capacity, and have little dependence on the orientation of the conformation capacity. BRIEF DESCRIPTION OF THE DRAWINGS [0029] FIG. 1 is a view showing the relationship between the average value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> and the minimum folding thickness / radius ratio of a hot rolled steel.
    [0030] FIG. 2 is a view showing the relationship between the average value of a random X-ray intensity ratio of a crystal orientation {332} <113> and the thickness / bending radius ratio
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    13/121 minimum of hot rolled steel sheet.
    [0031] FIG. 3 is a view showing the relationship between rC which is the r value in a direction perpendicular to the rolling direction and the minimum folding thickness / radius ratio of the hot-rolled steel sheet.
    [0032] FIG. 4 is a view showing the relationship between r30 which is the r value in a direction that forms an angle of 30 ° with respect to the rolling direction and the minimum folding thickness / radius ratio of the hot-rolled steel sheet.
    [0033] FIG. 5 is a view showing the relationship between rL which is the r value in the rolling direction and the minimum bending thickness / radius ratio of the hot rolled steel sheet.
    [0034] FIG. 6 is a view showing the relationship between r60 which is the r-value in a direction that forms an angle of 60 ° with respect to the rolling direction and the minimum folding thickness / radius ratio of the hot-rolled steel sheet.
    [0035] FIG. 7 is a view showing the relationship between the average value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> and the minimum thickness / radius ratio of the steel plate cold rolled.
    [0036] FIG. 8 is a view showing the relationship between the average value of the random X-ray intensity ratio of the crystal orientation {332} <113> and the minimum bending thickness / radius ratio of the cold rolled steel sheet.
    [0037] FIG. 9 is a view showing the relationship between rC which is the r value in the direction perpendicular to the rolling direction and the minimum bending thickness / radius ratio of the cold rolled steel sheet. [0038] FIG. 10 is a view showing the relationship between r50 which is the r value in the direction that forms an angle of 30 ° in relation to the rolling direction and the minimum thickness / radius of bending ratio of
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    14/121 cold rolled steel sheet.
    [0039] FIG. 11 is a view showing the relationship between rL which is the r value in the rolling direction and the minimum bending thickness / radius ratio of the cold rolled steel sheet.
    [0040] FIG. 12 is a view showing the relationship between r60 which is the r value in the direction that forms an angle of 60 ° in relation to the rolling direction and the minimum thickness / radius ratio of the cold rolled steel sheet.
    [0041] FIG. 13 is a view showing the relationship between the average value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> and the minimum thickness / radius of bending of the steel plate galvanized.
    [0042] FIG. 14 is a view showing the relationship between the average value of the random X-ray intensity ratio of the crystal orientation {332} <113> and the minimum bending thickness / radius ratio of the galvanized steel sheet.
    [0043] FIG. 15 is a view showing the relationship between r which is the r value in the direction perpendicular to the rolling direction and the minimum thickness / bending ratio of the galvanized steel sheet. [0044] FIG. 16 is a view showing the relationship between r30 which is the r value in the direction that forms an angle of 30 ° with respect to the rolling direction and the minimum folding thickness / radius ratio of the galvanized steel sheet.
    [0045] FIG. 17 is a view showing the relationship between r which is the r value in the rolling direction and the minimum bending thickness / radius ratio of the galvanized steel sheet.
    [0046] FIG. 18 is a view showing the relationship between r60 which is the r value in a direction that forms an angle of 60 ° with respect to the rolling direction and the minimum folding thickness / radius ratio of the galvanized steel sheet.
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    15/121 [0047] FIG. 19 is a view showing the relationship between the austenite grain diameter after rough rolling and rC which is the r value in the direction perpendicular to the rolling direction on the hot rolled steel sheet.
    [0048] FIG. 20 is a view showing the relationship between the austenite grain diameter after rough rolling and r30 which is the r value in the direction that forms an angle of 30 ° with respect to the rolling direction on the hot rolled steel sheet.
    [0049] FIG. 21 is a view showing the relationship between the number of rolling times at a rolling reduction ratio of 20% or more in the rough rolling and the grain diameter of the austenite after the rough rolling.
    [0050] FIG. 22 is a view showing the relationship between the total lamination reduction ratio in a temperature range from T1 + 30 ° C to T1 + 200 ° C and the average value of the random X-ray intensity ratio of a group of orientations { 100} <011> to {223} <110> on the hot rolled steel sheet.
    [0051] FIG. 23 is a view showing the relationship between the total lamination reduction ratio in a temperature range from T1 ° C to less than T1 + 30 ° C and the average value of the random X-ray intensity ratio of a group of orientations { 100} <011> to {223} <110> on the hot rolled steel sheet.
    [0052] FIG. 24 is a view showing the relationship between the ratio of total lamination reduction in a temperature range from T1 + 30 ° C to T1 + 200 ° C and the ratio of random X-ray intensity of the crystal orientation {332} <113 > on hot-rolled steel plate.
    [0053] FIG. 25 is a view m showing the relationship between the ratio of total lamination reduction in a temperature range from T1 ° C to less than T1 + 30 ° C and the random X-ray intensity ratio of the crystal orientation {332} < 113> on hot-rolled steel plate.
    Petition 870190036901, of 4/17/2019, p. 18/170
    16/121 [0054] FIG. 26 is a view showing the relationship between the amount of maximum temperature rise of the steel plate between the respective passes during rolling in a temperature range from T1 + 30 ° C to T1 + 200 ° C, the waiting time from the end of the final large reduction pass until the start of cooling in a case where the pass in which the lamination reduction ratio is 30% or more in the temperature range from T1 + 30 ° C to T1 + 200 ° C is defined as the large reduction pass, and rL which is the value r NBA rolling direction on hot rolled steel plate.
    [0055] FIG. 27 is a view showing the relationship between the amount of maximum temperature rise of the steel plate between the respective passes during rolling in a temperature range from T1 + 30 ° C to T1 + 200 ° C, the waiting time from the end of the final pass if large reduction until the start of cooling in a case where a pass in which the lamination reduction ratio is 30% or more in the temperature range from T1 + 30 ° C to T1 + 200 ° C is defined as a large reduction pass, and r60 which is the r value in the direction that forms an angle of 60 ° with respect to the rolling direction on the hot rolled steel sheet.
    [0056] FIG. 28 is a view showing the relationship between the diameter of the austenite grain after rough rolling and r which is the value r in the direction perpendicular to the direction of rolling in the cold rolled steel sheet.
    [0057] FIG. 29 is a view showing the relationship between the austenite grain diameter after rough rolling and r30 which is the value r in a direction that forms an angle of 30 ° with respect to the rolling direction on the cold rolled steel sheet.
    [0058] FIG. 30 is a view showing the relationship between the lamination reduction ratio from T1 + 30 ° C to T1 + 200 ° C and the average value of the random X-ray intensity ratio of a group of orientations
    Petition 870190036901, of 4/17/2019, p. 19/170
    17/121 {100} <011> to {223} <110> on cold rolled steel sheet. .
    [0059] FIG. 31 is a view showing the relationship between the total lamination reduction ratio in a temperature range from T1 + 30 ° C to T1 + 200 ° C and the random X-ray intensity ratio of the {332} <113 crystal orientation > on cold rolled steel sheet.
    [0060] FIG. 32 is a view showing the relationship between the austenite grain diameter after rough rolling and rC which is the r value in the direction perpendicular to the rolling direction on a galvanized steel sheet.
    [0061] FIG. 33 is a view showing the relationship between the austenite grain diameter after rough rolling and r30 which is the value r in a direction that forms an angle of 30 ° with respect to the rolling direction of the galvanized steel sheet.
    [0062] FIG. 34 is a view showing the relationship between the total lamination reduction ratio in a temperature range from T1 + 30 ° C to T1 + 200 ° C and the average value of the random X-ray intensity ratio of the {100 group of orientations } <011> to {223} <110> on the galvanized steel sheet.
    [0063] FIG. 35 is a view showing the relationship between the ratio of total lamination reduction in a temperature range from T1 ° C to less than T1 + 30 ° C and the average value of the random X-ray intensity ratio of the {100 group of orientations } <011> to {223} <110> on the galvanized steel sheet.
    [0064] FIG. 36 is a view showing the relationship between the total lamination reduction ratio in a temperature range from T1 + 30 ° C to T1 + 200 ° C and the random X-ray intensity ratio of the crystal orientation {332} <113 >.
    [0065] FIG. 37 is a view showing the relationship between the total lamination reduction ratio in a temperature range from T1 ° C to less than T1 + 30 ° C and the random X-ray intensity ratio of
    Petition 870190036901, of 4/17/2019, p. 20/170
    18/121 {332} <113> crystal orientation on the galvanized steel sheet.
    [0066] FIG. 38 is a view showing the relationship between the amount of maximum temperature rise of the steel plate between the respective passes during rolling in a temperature range from T1 + 30 ° C to T1 + 200 ° C, the waiting time from the end of the final large reduction pass until the start of cooling in a case where the pass in which the lamination reduction ratio is 30% or more in the temperature range from T1 + 30 ° C to T1 + 200 ° C is defined as a high reduction pass, and rL which is the r value in the rolling direction of the galvanized steel sheet.
    [0067] FIG. 39 is a view showing the relationship between the amount of maximum temperature rise of the steel plate between the respective passes during rolling in a temperature range from T1 + 30 ° C to T1 + 200 ° C, the waiting time from the termination of the final high reduction pass until the start of cooling in a case where the pass in which the lamination reduction ratio is 30% or more in the temperature range from T1 + 30 ° C to T1 + 200 ° C is defined thatch the large reduction pass, and r60 which is the r value in the direction that forms 60 ° in relation to the rolling direction on the galvanized steel sheet.
    [0068] FIG. 40 is a view showing the relationship between strength and bore expansion properties of the hot rolled steel sheet of the configuration and a comparative steel.
    [0069] FIG. 41 is a view showing the relationship between strength and folding properties of the hot rolled steel sheet of the configuration and comparative steel.
    [0070] FIG. 42 is a view showing the relationship between strength and anisotropy of the forming capacity of the hot-rolled steel sheet of the configuration and comparative steel.
    [0071] FIG. 43 is a view showing the relationship between resistance
    Petition 870190036901, of 4/17/2019, p. 21/170
    19/121 and hole expansion properties of the cold rolled steel sheet of the configuration and comparative steel.
    [0072] FIG. 44 is a view showing the relationship between strength and folding properties of the cold rolled steel sheet of the configuration and comparative steel.
    [0073] FIG. 45 is a view showing the relationship between strength and anisotropy of the forming capacity of the cold rolled steel sheet of the configuration and comparative steel.
    DESCRIPTION OF THE SETTINGS [0074] Hereinafter, a configuration of the present invention will be described in detail.
    1. For a hot-rolled steel sheet (1).
    [0075] The average value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> in a central portion of the thickness that is in a range of 5/8 to 3 / 8 from the steel plate surface, the random X-ray intensity ratio of a crystal orientation {332} <113>:
    [0076] The average value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> in a central portion of the plate thickness that is in a range from 5/8 to 3/8 from the steel sheet surface is a particularly important characteristic value of the configuration.
    [0077] As shown in FIG. 1, if the average value of the guidance group {100} <011> to {223} <110> is 6.0 or less when X-ray diffraction is performed on a plate surface in the central portion of the thickness that is in a strip of sheet thickness from 5/8 to 3/8 from the surface of the steel sheet so that the intensity ratios of the respective orientations in relation to a random specimen are obtained, d / Rm which is the thickness / minimum bending radius required to work the components inPetição 870190036901, from 04/17/2019, pg. 22/170
    20/121 bridges or frame components is 1.5 or more. In addition, in a case where bore expansion properties or small small folding characteristics are required, d / Rm is desirably 4.0 or less, and more preferably less than 3.0. When d / Rm is greater than 6.0, the anisotropy of the mechanical characteristics of the steel sheet becomes extremely strong, and consequently even when the local deformation capacity in a certain direction improves, the qualities of the material in directions other than the above direction degrade significantly, and therefore it is impossible for the ratio of sheet thickness / minimum bending radius to be greater than or equal to 1.5. In a case where the cold-rolled steel sheet or the hot-rolled steel strip that is the starting sheet for a galvanized steel sheet is used, the random X-ray intensity ratio is preferably less than 4.0 .
    [0078] Meanwhile, although it is difficult to perform in a common continuous hot rolling process today, when the random X-ray intensity ratio becomes less than 1.0, there is concern that the local deformation capacity may degrade .
    [0079] Furthermore, due to the same reason, if the ratio of random X-ray intensity of the crystal orientation {332} <113> in the central portion of the plate thickness which is in a 5/8 plate thickness range 3/8 from the steel plate surface is 5.0 or less as shown in FIG. 2, the minimum sheet thickness / bending radius required to work the lower components is 1.5 or more. The ratio of sheet thickness / minimum bending radius is more desirably 3.0 or less. When the sheet thickness / minimum bending radius ratio is greater than 5.0, the anisotropy of the mechanical characteristics of the steel sheet becomes extremely strong, and, consequently, even when capacity 870190036901, of 17/04/2019, p. . 23/170
    21/121 local deformation improves only in a certain direction, the qualities of the material in directions other than the above direction degrade significantly, and therefore it becomes impossible for the minimum sheet thickness / bending radius ratio to be greater than or equal to 1.5. Meanwhile, although it is difficult to perform in a current common continuous hot rolling process, when the random X-ray intensity ratio becomes less than 1.0, there is concern that the local deformation capacity may degrade.
    [0080] The reason why the random X-ray intensity ratio of the above crystal orientation is not important is important for the freezing properties of the shape during folding work, but the random X-ray intensity ratio is supposed to of the crystal orientation has a relationship with the sliding behavior of the crystals during the folding work.
    (2) rC which is the r value in the direction perpendicular to the rolling direction:
    [0081] rC is important in the configuration. That is, as a result of intensive studies, the inventors have found that favorable hole expansion properties or bending properties cannot always be obtained, even when only the random X-ray intensity ratios of the above variety of crystal orientations are adequate. As shown in FIG. 3, in addition to the random X-ray intensity ratio, rC must be 0.70 or more.
    [0082] When the upper limit of rC is set to 1.10, a more favorable local training capacity can be obtained.
    (3) r30 which is the r value in the direction that forms an angle of 30 ° in relation to the rolling direction:
    [0083] r30 is important in the configuration. That is, as a result of intensive studies, the inventors found that an ability to
    Petition 870190036901, of 4/17/2019, p. 24/170
    22/121 Favorable local deformation cannot always be obtained even when only the random X-ray intensity ratios of the above crystal orientations are adequate. As shown in FIG. 4, in addition to the random X-ray intensity ratio, r30 must be 1.10 or less.
    [0084] When the lower limit of r30 is set to 0.70, a more favorable local deformation capacity can be obtained.
    (4) rL which is the value r in the rolling direction and r60 which is the value r in the direction that forms an angle of 60 ° in relation to the rolling direction:
    [0085] In addition, as a result of intensive studies, the inventors found that, in addition to the random X-ray intensity ratios of the varieties of crystal orientations above, rC, and r30, when, in addition, rL in the lamination direction is 0.70 or more, and r60 which is the value r in the direction that forms an angle of 60 ° with respect to the rolling direction is 1.10 or less as shown in FIGs. 5 and 6, the sheet thickness / minimum bending radius> 2.0 ratio is satisfied.
    [0086] When the rL value and the r60 value are set to 1.10 or less and 0.70 or more respectively, a more favorable local deformation capacity can be obtained.
    [0087] Meanwhile, it is generally known that there is a correlation between the texture and the r-value, but in the hot-rolled steel plate according to the configuration, the limitation in the ratio of random X-ray intensity of the crystal orientation and the limitation of the r-value are not identical, and a favorable local deformation capacity cannot be obtained until both limitations are satisfied at the same time.
    (5) dL / dt ratios of bainite, martensite, perlite, and austenite grains:
    Petition 870190036901, of 4/17/2019, p. 25/170
    23/121 [0088] As a result of also investigating the local deformation capacity, the inventors found that when the texture and the r-value are satisfied, and also the equiaxial properties of the crystal grains are excellent, the dependence on the direction of work folding almost disappears. As an index that indicates equiaxial properties, the fraction of grains that has a dL / dt which is the ratio of dL which is the length of the crystal grains in the structure in the direction of hot rolling to dt which is the length in the direction of plate thickness of 3.0 or less, and are excellent in terms of equiaxial properties is 50% to 100% in crystal grains. When the fraction is less than 50%, the folding properties R in a direction L, which is the lamination direction, or a direction C, which is the direction perpendicular to the lamination direction, degrades.
    [0089] The respective structures can be determined as follows.
    [0090] Perlite is specified by observing the structure using an optical microscope. Next, the crystal structure is determined using electronic scattering diffraction (EBSD), and a crystal having a fcc structure is determined to be austenite. Ferrite, bainite, and martensite having a bcc structure can be recognized through the Average Kernel Disorientation with which EBSP-OIM TM is equipped, that is, through a KAM method. In the KAM method, between the measurement data, the orientation differences are averaged from the 6 pixels closest to a regular hexagonal pixel, from the nearest 12 seconds to the nearest pixels, or from the nearest 18 third pixels. the closest second pixels, and the value is computed by performing the calculation in which the average value is used as the central pixel value in the respective pixels. A map representing a change in orientation in a grain can be prepared using the calculation between
    Petition 870190036901, of 4/17/2019, p. 26/170
    12/24 grain edges. The map represents the stress distribution based on the change in local orientation in the grain.
    [0091] In the examples of the present invention, as a condition under which the difference in orientation between adjacent pixels in the EBSP-OIM ™ is calculated, the difference in orientation has been adjusted to 5 ° or less with respect to the third closest pixel, and a pixel having a difference in orientation in relation to the third pixel closest to more than 1 ° was defined as ferrite. This is because polygonal pro-eutectic ferrite transformed at a high temperature is generated through the diffusion transformation, and therefore the displacement density is small, and the tension in the grain is small so that the difference in crystal orientations in the small foot grain , and the fraction of volume of ferrite obtained from a variety of investigations that the inventors carried out using observation under an optical microscope and the fraction of area obtained in a difference of orientation in relation to the third pixel closest to 1 ° measured through the KAM method, are approximately compatible.
    (6) Fraction of the crystal grains having a grain diameter of more than 20 pm:
    [0092] In addition, it has been found that folding properties are strongly influenced by the equestrian properties of crystal grains and the effect is great. The reasons are not obvious, but it is considered that a folding deformation mode is one in which the stress is concentrated locally, and a state in which all the crystal grains are uniformly and equivalently tensioned is advantageous for the folding properties. It is considered that, in a case where there are many crystal grains having a large crystal diameter, even when the crystal grains are sufficiently made isotropic and equiaxial, the crystal grains tension locally, and a great variation in properties appears.
    Petition 870190036901, of 4/17/2019, p. 27/170
    25/121 of folding due to the orientation of the locally stretched crystal grains so that the folding properties are degraded. Therefore, in order to suppress the location of the tension and improve the folding properties by the effect of being made isotropic and equiaxial, the area fraction of the crystal grains having a diameter of more than 20 qm is preferably smaller, and needs to be 0% to 10 %. When the area fraction is greater than 10%, the folding properties deteriorate. The crystal grains mentioned here refer to crystal grains of ferrite, perlite, bainite, martensite and austenite. [0093] The present invention is generally applicable to hot rolled steel sheets, and, as long as the above limitations are satisfied, the local deformation capacity, such as bending work capacity or bore expansion properties of a steel sheet hot rolled, improve drastically without the limitation of combination of structures.
    2. For cold rolled steel sheet:
    (1) An average value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> in a central portion of the plate structure that is in a plate thickness range from 5/8 to 3/8 from the surface of the steel plate, and the random X-ray intensity ratio of a {332} <113> crystal orientation:
    [0094] The average value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> in a central portion of the plate thickness that is in a plate thickness range 5/8 to 3/8 from the steel sheet surface is particularly important for the configuration.
    [0095] As shown in FIG. 7, if the average value of the guidance group {100} <011> to {223} <110> is less than 4.0 when X-ray diffraction is performed on a plate surface at Portion 870190036901, from 17/04 / 2019, p. 28/170
    26/121 central indication of the plate thickness which is in a plate thickness range from 5/8 to 3/8 from the surface of the steel plate so that the intensity ratios of the respective orientations in relation to a random specimen are obtained, the minimum sheet thickness / bending radius required for the work of the structure components is 1.5 or more. In addition, in a case where bore expansion properties or a small bend characteristic limit is required, the minimum sheet steel / bending radius ratio is desirably less than 3.0. When the sheet thickness / minimum bending radius ratio is 4.0 or more, the anisotropy of the mechanical characteristics of the steel sheet becomes extremely strong, and consequently, even when the local deformation capacity in a certain direction improves, the material qualities in directions other than the above direction degrade significantly, and therefore it becomes impossible for the minimum folding plate / radius thickness to be greater than or equal to 1.5.
    [0096] Meanwhile, although it is difficult to perform in a current common continuous hot rolling process, when the random X-ray intensity ratio becomes less than 1.0, there is a concern that the local deformation capacity may degrade .
    [0097] Furthermore, due to the same reason, if the ratio of random intensity of X-rays of the crystal orientation {332} <113> in the central portion of the thickness of the plate which is in a thickness range from 5/8 to 3 / 8 from the surface of the steel plate is 5.0 or less as shown in FIG. 8, the minimum sheet thickness / bending radius ratio required for working frame components is 1.5 or more. The ratio of sheet thickness / minimum bending radius is more desirably 3.0 or less. When the sheet thickness / minimum bending radius ratio is more than 5.0, the anisotropy of the mechanical characteristics of the steel sheet becomes
    Petition 870190036901, of 4/17/2019, p. 29/170
    27/121 extremely strong, and consequently, even when the local deformation capacity improves only in a certain direction, the qualities of the material in directions other than the above direction degrade significantly, and therefore it becomes impossible for the plate thickness / radius ratio minimum bend is equal to or greater than 1.5. Meanwhile, although it is difficult to perform in a common continuous hot rolling process today, when the random X-ray intensity becomes less than 1.0, there is concern that the local deformation capacity may degrade.
    [0098] The reason why the random X-ray intensity ratio of the above crystal orientation is not important is important for the freezing properties of the shape during folding work, but the random X-ray intensity ratio is supposed to has to do with the sliding behavior of the crystals during the folding work.
    (2) rC which is the r value in the direction perpendicular to the rolling direction:
    [0099] rC is important in the configuration. That is, as a result of intensive studies, the inventors have found that favorable bore expansion properties or folding properties cannot always be obtained even when only the random X-ray intensity ratios of the above variety of crystal orientations are adequate. As shown in FIG. 9, in addition to the random X-ray intensity ratio. Should be 0.70 or more. C [00100] When the upper limit of rC is set to 1.10, a more favorable local deformation capacity can be obtained.
    (3) r30 which is the r value in the direction that forms an angle of 30 ° in relation to the rolling direction:
    [00101] r30 is important in the configuration. That is, as a result of intensive studies, the inventors found that a
    Petition 870190036901, of 4/17/2019, p. 30/170
    28/121 Favorable local deformation cannot always be obtained, even when only the random X-ray intensity ratios in the variety of crystal grain orientations above are adequate. As shown in FIG. 10, in addition to the random X-ray intensity ratio, r30 must be 1.10 or less.
    [00102] When the lower limit of r30 is set to 0.70. a more favorable local deformation capacity can be obtained.
    (4) rL which is the value r in the rolling direction and r60 which is the value r in the direction that forms an angle of 60 ° in relation to the rolling direction:
    [00103] Furthermore, as a result of intensive studies, the inventors have found that, in addition to the random X-ray intensity ratios of the above crystal range, rC and r30, when, in addition, rL in the lamination direction is 0.70 or more, and r60 which is the value in the direction which forms an angle of 60 ° with respect to the rolling direction is 1.10 or less as shown in FIGS. 11 and 12, the sheet thickness / minimum bending radius ratio is equal to or greater than 2.0.
    [00104] When rL and r60 are set to 1.10 or less and 0.70 or more respectively, a more favorable local deformation capacity can be obtained.
    [00105] Meanwhile, it is generally known that there is a correlation between the texture and the r value, in the cold rolled steel plate according to the configuration, the limitation of the X-ray random intensity ratio of the crystal orientation and the limitation of the r-values are not identical, and a favorable local deformation capacity cannot be obtained unless both limitations are satisfied at the same time.
    (5) The dL / dt ratios of grains of bainite, martensite, perlite, and austenite:
    Petition 870190036901, of 4/17/2019, p. 1/31
    29/121 [00106] As a result of also investigating the local deformation capacity, the inventors found that when the texture and the r-value are satisfied, and also the equiaxial properties of the crystal grains are excellent, the dependence on the direction of work folding almost disappears. As an index that indicates equiaxial properties, it is important that the fraction of the grains having a dL / dt, which is the ratio of dL which is the length of the crystal grains in the structure in the direction of the cold rolling for dt which is the length in the direction of plate thickness, 3.0 or less, and are excellent in terms of equiaxial properties is 50% to 100% in crystal grains. When the fraction is less than 50%, the folding properties R in the L direction which is the lamination direction or in the C direction which is the direction perpendicular to the lamination direction, degrades.
    [00107] The respective structures can be determined as follows.
    [00108] Perlite is specified by observing the structure using an optical microscope. Next, the crystal structure is determined using electronic scattering diffraction (EBSD), in crystal having a fcc structure it is determined to be austenite. Ferrite, bainite, and martensite having a bcc structure can be recognized through the Media Kernel Disorientation with which the EBSP-OIM TM is equipped, that is, through a KAM method. In the KAM method, between the measurement data, the orientation differences of 6 pixels closest to a regular hexagonal pixel, 12 seconds closest to the nearest pixels, or the 18 nearest third outside pixels are averaged the second closest pixels, and the value is computed by performing the calculation in which the average value is used as the central pixel value in the respective pixels. A map that represents a change of orientation in, a grain can be
    Petition 870190036901, of 4/17/2019, p. 32/170
    12/30 prepared by performing the calculation at the grain edges. The map represents the stress distribution based on the change in local orientation in the grain.
    [00109] In the examples of the present invention, as a condition under which the difference in orientation between adjacent pixels in EBSP-OIM ™, the difference in orientation was adjusted to 5 ° or less with respect to the third closest pixel, and one pixel having a difference in orientation in relation to the third pixel closest to more than 1 ° was defined as bainite or martensite, which is a low temperature transformation product, and one pixel having a difference in orientation in relation to the third pixel closest to 1 ° or less was defined as ferrite. This is because pro-eutectic polygonal ferrite transformed at a high temperature is generated by the transformation of diffusion, and therefore the displacement density is small, and the tension in the grain is small, and the volume fraction of ferrite obtained from a The variety of investigations that the inventors carried out using observation under an optical microscope and the fraction of area obtained at a difference in orientation of the third pixel closest to 1 ° measured using the KAM method are approximately equivalent.
    (6) Fraction of crystal grains having a grain diameter of more than 20 pm:
    [00110] Furthermore, it has been found that folding properties are strongly influenced by the equiaxial properties of crystal grains, and the effect is great. In addition, it has been found that folding properties are strongly influenced by the equiaxial properties of crystal grains, and the effect is great. The reasons are not obvious, but bending deformation is considered to be a mode in which the stress is concentrated locally, and a state in which all the crystal grains are uniformly and equivalently tensioned is advantageous for the bending propertiesPetition 870190036901, de 04/17/2019, p. 33/170
    12/31 ment. It is considered that, in a case where there are many crystal grains having a large grain diameter even when the crystal grains are sufficiently made to be isotropic and equiaxial crystal grains tension locally, and a great variation appears in the folding properties due to the orientation of locally stretched crystal grains so that degradation of folding properties is caused. Therefore, in order to suppress the location of the stress and improve the folding properties through the effect of making it isotropic and equiaxial, the area fraction of the crystal grains that have a large diameter of more than 20 qm is preferably smaller, and needs to be 0% to 10%. When the area fraction is greater than 10%, the folding properties deteriorate. The crystal grains mentioned here refer to crystal grains of ferrite, perlite, bainite, martensite and austenite [00111] The present invention is generally applicable to cold rolled steel sheets, and, provided the above limitations are satisfied, the local deformation capacity, such as bending work capacity or hole expansion properties of cold rolled steel sheet, improves dramatically without limitation in the combination of structures.
    3. Regarding the galvanized steel sheet (1) An average value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> in a central portion of the sheet thickness that is in the plate thickness range from 5/8 to 3/8 from the surface of the steel plate, the random X-ray intensity ratio of a {332} <113> crystal orientation:
    [00112] The average value of the random X-ray intensity ratio of a group of orientations {100} <011> to {223} <110> in a central portion of the thickness of the plate that is in a range of thickness 870190036901, from 04/17/2019, p. 34/170
    32/121 sura of the plate from 5/8 to 3/8 from the surface of the steel plate is particularly important in the configuration. As shown in FIG. 13, if the average value of the guidance group {100} <011> to {223} <110> is less than 4.0 when X-ray diffraction is performed on a plate surface in the central portion of the plate thickness that is in a range of plate thickness from 5/8 to 3/8 from the surface of the steel plate so that the intensity ratios of the respective orientations in relation to the random specimen are obtained, the ratio of plate thickness / radius of Minimum bending required for working lower components or frame components is 1.5 or more. In addition, in a case where hole expansion properties or a small bend limit characteristic is required, the minimum sheet thickness / bending radius ratio is desirably less than 3.0. When the sheet thickness / minimum bending radius ratio is 4.0 or more, the anisotropy of the mechanical characteristics of the steel sheet becomes extremely strong, and consequently, even when the local deformation capacity in a certain direction improves, the material qualities in directions other than the above direction degrade significantly, and therefore it is impossible for the sheet thickness / minimum bending radius ratio to be greater than or equal to 1.5. [00113] Meanwhile, although it is difficult to perform in a current common continuous hot rolling process, when the random X-ray intensity ratio becomes less than 1.0. there is a concern that the local deformation capacity may degrade.
    [00114] In addition, due to the same reason, if the ratio of random X-ray intensity of the crystal orientation {332} <113> in the central portion of the plate thickness which is in a plate thickness range from 5/8 to 3/8 from the steel sheet surface is 5.0 or less as shown in FIG. 14, the plate thickness /
    Petition 870190036901, of 4/17/2019, p. 35/170
    33/121 Minimum bending radius required for working lower components is 1.5 or more. The ratio of sheet thickness / minimum bending radius is more desirably 3.0 or less. When the sheet thickness / minimum bending radius ratio is greater than 5.0, the anisotropy of the mechanical characteristics of the steel sheet becomes extremely strong, and consequently, even when the local deformation capacity improves only in a certain direction, the qualities of the material in directions other than the above direction degrade significantly, and therefore it is impossible to reliably satisfy the minimum sheet thickness / bending radius> 1.5 ratio. Meanwhile, while it is difficult to perform in a current common continuous hot rolling process, when the random X-ray intensity ratio becomes less than 1.0, there is concern that the local deformation capacity may degrade.
    [00115] The reason why the random X-ray intensity ratio of the above crystal orientation is not important is important to the freezing properties of the shape during folding work, but the random X-ray intensity ratio is supposed to of the crystal orientation has a relationship with the sliding behavior of the crystals during the folding work.
    [00116] rC which is the value r in the direction perpendicular to the lamination direction:
    [00117] rC is important for the configuration. That is, as a result of intensive studies, the inventors have found that favorable bore expansion properties or folding properties cannot always be obtained even when only the random X-ray intensity ratios of the above crystal orientations are adequate. As shown in FIG. 15, in addition to the random X-ray intensity ratio, rC must be 0.70 or more.
    Petition 870190036901, of 4/17/2019, p. 36/170
    34/121 [00118] When the upper limit of rC is set to 1.10, a more favorable local deformation capacity can be obtained. [00119] r30 which is the r value in the direction that forms an angle of 30 ° in relation to the rolling direction:
    [00120] r30 is important in the configuration. That is, as a result of intensive studies, the inventors have found that bore expansion properties or bending properties cannot always be obtained when only the random X-ray intensity ratios of the above crystal orientations are adequate. As shown in FIG. 16, in addition to the random X-ray intensity ratio, r30 must be 1.10 or less.
    [00121] When the lower limit of r30 is set to 0.70, a more favorable local deformation capacity can be obtained. [00122] rL which is the r value in the lamination direction, and r60 which is the r value in a direction that forms an angle of 60 ° in relation to the lamination direction:
    [00123] In addition, as a result of intensive studies, the inventors found that, in addition to the random X-ray intensity ratios of the above crystal orientation range, rC, and r30, when, in addition, rL in the lamination direction and 0.70 or more, and r60 which is the r value in a direction that forms an angle of 60 ° with respect to the rolling direction is 1.10 or less as shown in FIGS, 17 and 18, the plate thickness ratio / minimum bending radius will be greater than or equal to 2.0. When the rL value and the r60 value are set to 1.10 or less and 0.70 or more, respectively, a more favorable local deformation capacity can be obtained. [00124] Meanwhile, it is generally known that there is a correlation between texture and the r value, in the galvanized steel sheet according to the present invention, the limitation of the X-ray intensity of the crystal orientation and the limitation of the r value are not are identical to each other, and a
    Petition 870190036901, of 4/17/2019, p. 37/170
    35/121 favorable local deformation capacity cannot be obtained until both limitations are satisfied at the same time. [00125] The present invention is generally applicable to galvanized steel sheets, e.g. as long as the above limitations are satisfied, the local deformation capacity, such as bending workability or hole expansion properties of a galvanized steel sheet, dramatically improves without limitation in a combination of structures.
    [00126] The main guidelines included in guidance group {100} <011> to {223} <110> are {100} <011>, {116} <110>, {114} <110>, {113} < 110>, {112} <110>, {335} <110>, and {223} <110>.
    [00127] The random X-ray intensity ratios of the respective orientations can be measured using a method such as X-ray diffraction or electronic scattering diffraction (EBSD). Specifically, the random 0-ray intensity can be obtained from a computed three-dimensional texture using a vector method based on the pole figure {110} or a computed three-dimensional texture using a series expansion method using a plurality of pole figures (preferably three or more) between {110}, {100}, {211}, and {310} pole figures.
    [00128] For example, as random X-ray intensity ratios of the respective crystal orientations in the EBSD method, the intensities of (001) [1-10], (116) [1-10], (114) [1- 10], (113) [1-10], (112) [110], (335) [1-10], and (223) [1-10] in a cross section φ2 = 45 ° of a three-dimensional texture can be used as they are. 1 with an upper bar indicating negative 1 is expressed by -1.
    [00129] In addition, the average value of the guidance group {100} <011> to {223} <110> is the arithmetic mean of the respective guidelines. In a case where the intensities of all of the above guidelines cannot be obtained, the intensity can be replaced by
    Petition 870190036901, of 4/17/2019, p. 38/170
    36/121 arithmetic mean of the respective orientations of {100} <011>, {116} <110>, {114} <110>, {112} <110>, and {223} <110>.
    [00130] For measurement, a specimen supplied by X-ray diffraction or EBSD is subjected to mechanical polishing or similar so that the steel plate is reduced from the surface to have a predetermined plate thickness, then the tension is removed through chemical polishing, and at the same time, the specimen is adjusted by the above method so that a suitable surface in a plate thickness range from 5/8 to 3/8 becomes the measuring surface. The specimen is desirably taken from a location 1/4 or ¾ of the width from the end portion towards the width of the plate; [00131] Needless to say, when the limitation of X-ray intensity is satisfied not only in the vicinity of ½ the thickness of the plate but also in as many thicknesses as possible, the local deformation capacity becomes more favorable. However, since, generally, the material characteristics of the entire steel sheet can be represented by measuring the central portion of the sheet thickness which is in a range of sheet thickness from 5/8 to 3/8 from the surface of the steel plate, the average value of the random X-ray intensity ratios of the guidance group {100} <011> to {223} <110> in the central portion of the plate thickness which is the range of the plate thickness 5/8 to 3/8 from the steel plate surface and the random X-ray intensity ratio of the {332} <113> crystal orientation are specified. The crystal orientation that is represented by {hkl} <uvw> indicates that the normal direction of the plate's surface is parallel to {hkl}, and the lamination direction is parallel to <uvw>.
    [00132] In addition, the respective r values are evaluated through tensile tests in which JIS No. 5 specimens are used. In the case of a high-strength steel plate, the tensile stress
    Petition 870190036901, of 4/17/2019, p. 39/170
    37/121 can be evaluated in a range of 5% to 15% using a uniform elongation range.
    [00133] Since the direction in which the folding work is performed varies by the components to be worked on, the direction is not particularly limited, however, according to the present invention, the same characteristics can be obtained in all directions of folding.
    [00134] The dL / dt and the perlite grain diameter can be obtained through binarization and the method of counting points in the observation of the structure using an optical microscope.
    [00135] In addition, the grain diameters of ferrite, bainite, martensite, and austenite can be obtained by measuring the orientations for example, at a magnification of 1500 times and the measurement step (of extreme intensity) of 0.5 pm or less in an analysis of the orientations of the steel plate using the EBSD method, specifying the locations in which the difference in orientation between adjacent measuring points exceeds 15 ° as grain edges, and obtaining an equivalent circle diameter. At that moment, the lengths of a grain in the rolling direction and the direction of the sheet thickness are obtained at the same time, thus obtaining dL / dt.
    [00136] The conditions for limiting the steel plate components will be described below. The% for the contents is% by mass. [00137] Since the cold-rolled steel sheet and the galvanized steel sheet of the present invention use the hot-rolled steel sheet of the present invention as the base sheet, the steel sheet components will be as follows for all hot rolled steel sheets. Cold rolled steel sheets and galvanized steel sheets.
    [00138] C is an element basically included, and the reason why the lower limit is set to 0.0001% is to use the lower limit value obPetition 870190036901, from 17/04/2019, p. 40/170
    38/121 in practice. When the upper limit exceeds 0.40%, the working capacity or the welding capacity deteriorates, and therefore the upper limit is adjusted to 0.40%. Meanwhile, since an excessive addition of C significantly deteriorates the spot welding capacity, the upper limit is more desirably set to 0.30% or less.
    [00139] Si is an effective element to increase the mechanical resistance of a steel plate and, when the content exceeds 2.5%, the work capacity deteriorates, or surface defects are generated, and therefore the upper limit is adjusted to 2.5%. On the other hand, since it is difficult to include Si in less than 0.001% in steel in practice, the lower limit is adjusted to 0.001%.
    [00140] Mn is an effective element to increase the mechanical resistance of a steel sheet, and when its content exceeds 4.0%, the work capacity deteriorates, and therefore the upper limit is adjusted to 4.0%. On the other hand, since it is difficult to include Mn at less than 0.001% in steel in practice, the lower limit is adjusted to 0.001%. However, to avoid an extreme increase in steel production costs, the lower limit is desirably adjusted to 0.01% or more. Since Mn suppresses the generation of ferrite, in a case where it is intended to include a ferrite phase in a structure in order to guarantee elongation, the lower limit is desirably adjusted to 3.0% or less. In addition, and, in a case where, in addition to Mn, elements that suppress the generation of hot cracks caused by S, such as Ti, are not added, Mn is desirably added in an amount so that Mn / S is becomes equal to or greater than 20 in terms of% in mass.
    [00141] The upper limits of P and S are 0.15% or less and 0.03% or less, respectively, to avoid deterioration of working capacity or cracking during hot rolling or
    Petition 870190036901, of 4/17/2019, p. 41/170
    39/121 cold rolling. The respective lower limits are adjusted to 0.001% for P and 0.0005% for S which are values obtained through current common purification (including secondary purification). Meanwhile, since extreme desulfurization significantly increases costs, the lower limit of S is more desirably 0.001% or more.
    [00142] For deoxidation, Al is added to 0.001% or more. However, in a case where sufficient deoxidation is required, Al is most desirably added to 0.01% or more. In addition, since Al significantly increases the transformation point γ ^ α from γ to a, Al is an effective element in a case where hot rolling particularly at point Ar3 or less is oriented. However, when Al is excessive, the welding capacity deteriorates, and therefore the upper limit is adjusted to 2.0%.
    [00143] N and O are impurities, and both are adjusted to 0.01% or less in order to prevent the work capacity from degrading. The lower limits are set to 0.0005% which is a value that can be obtained through the current common purification (including secondary purification) for both elements. However, the levels of N and O are desirably adjusted to 0.001% or more to suppress an extreme increase in steel production costs.
    [00144] In addition, to increase mechanical strength by reinforcing precipitation, or to control inclusions or precipitates from the refining to improve local deformation capacity, steel may contain one or two or more between any of the Ti elements , Nb, B, Mg, rare earths, Ca, Mo, Cr, V, W, Cu, Ni, Co, Sn, Zr, and As that have been used so far. To achieve enhanced precipitation, it is effective to generate fine carbonitrides, and the addition of Ti, Nb, V, or W is effective. In addition, Ti, Nb, V, and W also have an effect of contributing to the refining of crystal grains as solid solution elements.
    Petition 870190036901, of 4/17/2019, p. 42/170
    40/121 [00145] To obtain the effect of reinforcing precipitation through the addition of Ti, Nb, V, or W, it is necessary to add 0.001% or more of Ti, 0.001% or more of Nb, 0.001% or more of V , or 0.001% or more of W. In a case where increased precipitation is particularly necessary, it is more desirable to add 0.01% or more of Ti, 0.005% or more of Nb, 0.01% or more of V , or 0.01% or more of W. In addition, Ti and Nb have an effect of improving the quality of the material through mechanisms for fixing carbon and nitrogen, controlling the structure, reinforcing the fine grain, and the like in addition to increased precipitation. In addition, V is effective for reinforcing precipitation, causes less degradation of the local deformation capacity induced from the reinforcement due to the addition than Mo or Cr, and an effective addition element in a case where high strength and better properties hole expansion or folding properties are required. However, even when the above elements are added excessively, since the effect of an increase in strength is saturated, and furthermore, the recrystallization after hot rolling is suppressed so that it is difficult to control the crystal orientation, it is it is necessary to add Ti and Nb to 0.20% or less and V and W to 1.0% or less. However, in a case where elongation is particularly necessary, it is more desirable to include V at 0.50% or less and W at 0.50% or less.
    [00146] In a case where the hardening capacity of a structure is increased, and a second phase is controlled in order to guarantee strength, it is effective to add one or two or more elements between B, Mo, Cr, Cu, Ni , Co, Sn, Zr, and As. In addition, in addition to the above effect, B has an effect of improving the quality of the material through mechanisms for fixing carbon and nitrogen, controlling the structure, strengthening the fine grain, and the like . In addition, in addition to the effect of increasing mechanical strength, Mo and Cr have the effect of
    Petition 870190036901, of 4/17/2019, p. 43/170
    41/121 improve the quality of the material.
    [00147] To obtain the above effects, it is necessary to add B at 0.0001% or more, Mo, Cr, Ni, and Cu at 0.001% or more, and Co, Sn, Zr, and As at 0.0001% or more. However, in contrast, since an excessive addition deteriorates the working capacity, the upper limit of B is set to 0.0050%, the upper limit of Mo is set to 1.0%, the upper limits of Cr, Ni , and Cu are adjusted to 2.0%, the upper limit of Co is adjusted to 1.0%, the upper limits of Sn and Zr are adjusted to 0.2%, and the upper limit of As is adjusted to 0, 50%. In a case where there is a strong demand for work capacity, it is desirable to adjust the upper limit of B to 0.005% and the upper limit of Mo to 0.50%. In addition, it is more desirable to select B, Mo, Cr and As among the addition elements above the cost point of view.
    [00148] Mg, rare earths, and Ca are important addition elements that detoxify inclusions and also improve local deformation capacity. The lower limits for obtaining the above effect are 0.0001% respectively; however, in a case where it is necessary to control the forms of the inclusions, Mg, rare earths, and Ca are desirably added to 0.0005% or more respectively. Meanwhile, since an excessive addition results in cleaning degradation, the upper limits for Mg, rare earth, and Ca are set to 0010%, 0.1%, and 0.010% respectively.
    [00149] The effect of improving local deformation capacity is not lost even when the surface treatment is carried out on the hot-rolled steel sheet and the cold-rolled steel sheet of the present invention, and the effects of the present invention can be obtained even when anyone between electrodeposition, hot immersion, deposition coating, organic membrane formation, film lamination, a treatment with organic salts / inorPetition salts 870190036901, of 17/04/2019, p. 44/170
    42/121 genics, non-chrome treatment, and the like is performed.
    [00150] In addition, the galvanized steel sheet of the present invention has a galvanized layer by carrying out a galvanizing treatment on the surface of the cold rolled steel sheet of the present invention, and galvanizing can achieve the effects of both dip galvanizing both hot and electroplating. In addition, the galvanized steel sheet of the present invention can be produced as a zinc alloy coated steel sheet used primarily for automobiles by performing a bonding treatment after galvanizing.
    [00151] Additionally, the effects of the present invention are not lost even when the surface treatment is also performed on the high-strength galvanized steel sheet of the present invention, and the effects of the present invention can be obtained even when anyone between electroplating, hot dipping, deposition coating, organic membrane formation, film lamination, a treatment with organic salts / inorganic salts, non-chrome treatment, and the like is performed.
    2. Regarding the production method [00152] Next, the production method of a hot rolled steel sheet according to the configuration will be described.
    [00153] In order to achieve excellent local deformation capacity, it is important to form the texture having a predetermined random X-ray intensity ratio, satisfy the conditions for the r values in the respective directions, and control the shapes of the grains. Details of the production conditions to satisfy the above will be described below.
    [00154] The production method that precedes hot rolling is not particularly limited. That is, subsequent to casting using a blast furnace, an electric furnace, or similar, a variety of
    Petition 870190036901, of 4/17/2019, p. 45/170
    43/121 secondary purifications are performed, so the ingot can be cast using a method such as ordinary continuous casting, a conventional casting method, or thin plate casting. In the case of continuous casting, the ingot can be cooled down to a low temperature, reheated, and then hot rolled, or a cast plate can also be hot rolled in the state after casting without cooling the cast plate to a low temperature. . Scrap can be used as raw material. [00155] The hot rolled steel sheet according to the configuration is obtained in a case in which the following conditions are satisfied.
    [00156] In order to satisfy the predetermined values above rC of 0.70 or more and r30 of 1.10 or less, the diameter of the austenite grain after roughing lamination, that is, before finishing lamination is important. As shown in FIGS. 19 and 20, the grain diameter of the austenite before finishing lamination can be 200 pm or less.
    [00157] In order to obtain the austenite grain diameter before the finishing lamination of 200 pm or less in the roughing lamination, it is necessary to laminate in a temperature range of 1000 ° C to 1200 ° C and perform the lamination once or plus a lamination reduction ratio of at least 20% or more in the temperature range as shown in FIG. 21. However, to also increase homogeneity and increase elongation and local deformation capacity, it is desirable to perform lamination once or more at a lamination reduction ratio of at least 40% or more over a temperature range of 1000 ° C to 1200 ° C.
    [00158] The austenite grain diameter is most desirably set to 100 pm or less, and in order to reach the austenite grain diameter of 100 pm or less, it is desirable to perform lamination
    Petition 870190036901, of 4/17/2019, p. 46/170
    44/121 twice or more at a lamination reduction ratio of 20% or more. Desirably, lamination is performed twice or more at a lamination reduction ratio of 40% or more. as the lamination reduction ratio and the number of lamination times increase, smaller grains can be obtained, but there is a concern that the temperature may decrease or scalings may be excessively generated when the lamination exceeds 70% or the number of times the roughing lamination exceeds 10 times. As such, a decrease in the grain diameter of the austenite before the finishing lamination is effective in improving the local deformation capacity by accelerating the recrystallization of the austenite during the subsequent finishing lamination, particularly through the control of rL or r30.
    [00159] The reason why refining the austenite grain diameter has an influence on the local deformation capacity is supposed to be that the edges of the austenite grains after roughing lamination, that is, the edges of the austenite grains before lamination finishing products work as one of the recrystallization cores during the finishing lamination.
    [00160] To confirm the diameter of the austenite grain after roughing lamination, it is desirable to cool the plate part that is going to undergo the finishing lamination as quickly as possible. The plate part is cooled at a cooling rate of 10 ° C / s or more, the structure in the cross section of the steel sheet is etched, the edges of the austenite grains are shown, and the grain diameter of the austenite is measured using an optical microscope. At that time, the austenite's grain diameter is measured at a magnification of 50 times or more at 20 locations or more through image analysis or a point counting method.
    [00161] In addition, to reach an average value of the InPetition ratio 870190036901, of 4/17/2019, p. 47/170
    45/121 random X-ray tension of the {100} <011> to {223} <110> orientation group in a central portion of the structure that is in a plate thickness range from 5/8 to 3/8 from of the plate surface and a random X-ray intensity ratio of the crystal orientation {332} <113> in the values of the above ranges, based on the T1 temperature described in formula 1 which is determined by the steel plate components at the end of the lamination after roughing lamination, work is carried out at a high rate of lamination reduction in a temperature range from T1 + 30 ° C to T1 + 200 ° C, desirably in a temperature range from T1 + 50 ° C to T1 + 100 ° C, and work is performed at a small rate of rolling reduction in a temperature range of T1 ° C to less than T1 + 30 ° C. According to the above, the local deformation capacity and the shape of a hot rolled end product can be guaranteed. FIGS. 22 to 25 show the relationship between the lamination reduction ratios in the respective temperature ranges and the random X-ray intensity ratios of the respective orientations.
    [00162] That is, as shown in FIGS. 22 and 24, a large reduction in a temperature range from T1 + 30 ° C to T1 + 200 ° C and the subsequent lamination to T1 ° C less than T1 + 30 ° C as shown in FIGS. 23 and 25 controls the mean value of the random X-ray intensity ratio of the orientation group {100} <011> to {223} <110> in a central portion of the thickness that is in a plate thickness range of 5 / 8 to 3/8 from the steel plate surface and the random X-ray intensity ratio of the {332} <113> crystal orientation in order to dramatically improve the local deformation capacity of the hot-rolled final product.
    [00163] The temperature T1 is obtained experimentally, and the inventors discovered from experiments that the recrystallization in the austenite range of the respective steels is accelerated with the temperature T1
    Petition 870190036901, of 4/17/2019, p. 48/170
    46/121 as a basis.
    [00164] In order to obtain a more favorable local deformation capacity, it is important to accumulate tension through a large reduction or by repeatedly recrystallizing the structure in the entire lamination. To accumulate tension, the total reduction ratio is 50% or more, and desirably 70% or more, and in addition, the increase in the temperature of the steel plate between passes is desirably adjusted to 18 ° C or less. Meanwhile, a total lamination reduction of more than 90% is not desirable from the point of view of guaranteeing the temperature or excessive lamination load. In addition, to increase the homogeneity of a hot-rolled sheet, and to increase the local deformation capacity to the extreme, between the rolling passes at a temperature range of T1 + 30 ° C to T1 + 200 ° C, at least one pass is performed at a lamination reduction ratio of 30% or more, and desirably 40% or more. Meanwhile, when the lamination reduction ratio exceeds 70% in one pass, there is a concern that the shape may be impaired. In a case where there is a demand for a more favorable work capacity, it is more desirable to adjust the lamination reduction ratio to 30% or more in the final 3 passes.
    [00165] Furthermore, in order to accelerate uniform recrystallization by releasing the accumulated tension, it is necessary to suppress as much as possible the amount of work in a temperature range from T1 ° C to less than T1 + 30 ° C after the large reduction to T1 + 30 ° C to T1 + 200 ° C, and the total lamination rate at T1 ° C less than T1 + 30 ° C is adjusted to less than 30%. A rolling reduction ratio of 10% or more is desirable from the perspective of the steel sheet, but a rolling reduction ratio of 0% is desirable in a case where the local deformation capacity is more important. When the lamination reduction ratio at T1 ° C to less than T1 + 30 ° C exceeds
    Petition 870190036901, of 4/17/2019, p. 49/170
    47/121 a predetermined range, recrystallized austenite grains are expanded, and, when the retention time is short, the recrystallization does not proceed sufficiently, and the local deformation capacity deteriorates. That is, in production conditions depending on the configuration, it is important to recrystallize the austenite evenly and finely during the finishing lamination in order to control the texture of the hot rolled product to improve the local deformation capacity, as well as bore expansion properties or folding properties.
    [00166] When lamination is performed at a temperature lower than the temperature range specified above or at a lamination reduction ratio greater than the specified lamination reduction ratio, the austenite texture develops, and the random intensity ratios of X-rays in the respective crystal orientations, such as the average value of the random X-ray intensity ratio of the orientation group {100} <011> to {223} <110> at least in a central portion of the thickness that is in a plate thickness range from 5/8 to 3/8 from the steel plate surface of 6.0 or less and the random X-ray intensity ratio of the {332} <113> crystal orientation of 5.0 or less, it cannot be obtained in the finally obtained hot rolled steel sheet.
    [00167] Meanwhile, when lamination is performed at a temperature higher than the specified temperature range or at a lower lamination reduction ratio than the specified lamination reduction ratio, it results in coalescence of the grain or duplex grains, and the area fraction of crystal grains that have a grain diameter of more than 20 pm increases. Whether the lamination specified above is performed or not can be determined from the ratio of lamination reduction, lamination load, sheet thickness measurement, or the like through current calculation performance. In addition 870190036901, of 17/04/2019, p. 50/170
    48/121 tion, since the temperature can also be measured if a thermometer is present between the lamination chairs, and the calculation simulation in which the generation of working heat and the like is considered from the line speed, the lamination reduction ratio and the like is available, whether the lamination specified above is performed or cannot be determined using one or both between temperature and calculation simulation.
    [00168] Hot rolling performed in the above manner ends at an Ar3 temperature or higher. When the hot rolling finish temperature is less than Ar3, since rolling in a two-phase region in an austenite area and in a ferrite area is included, the accumulation in the {100} <011 orientation group > to {223} <110> becomes strong, and, consequently, the local deformation capacity degrades significantly.
    [00169] As long as rL and r60 are 0.70 or more and 1.10 or less respectively, in addition, a favorable sheet thickness / minimum bending radius> 2.0 ratio is satisfied. To achieve the minimum sheet thickness / bending radius ratio> 2.0, in a case where a pass in which the lamination reduction ratio is 30% or more in the temperature range from T1 + 30 ° C to T1 + 200 ° C is defined as the large reduction pass, the waiting time t (seconds) from the end of the large reduction pass until the start of cooling satisfies formula 2, and the increase in the temperature of the steel plate between the respective passes is desirably 18 ° C or less.
    [00170] FIGS. 26 and 27 show the relationship between the amount of increase in the temperature of the steel plate between passes during rolling at T1 + 30 ° C to T1 + 200 ° C; the waiting time t, and rL and r60. In a case where the increase in the temperature of the steel sheet between the respective passes at T1 + 30 ° C to T1 + 200 ° C is 18 ° C or less, and t meets formula 2, it is possible to obtain uniform recrystallized austenite
    Petition 870190036901, of 4/17/2019, p. 51/170
    49/121 having an rL of 0.70 or more and an r60 of 1.10 or less.
    [00171] When the waiting time t exceeds t1x2.5, the grain coalesce, and the elongation degrades significantly. In addition, when the waiting time t is shorter than t1, anisotropy increases, and the proportion of equiaxial grains decreases.
    [00172] In a case where the temperature rise of the steel sheet at T1 + 30 ° C to T1 + 200 ° C is too low to obtain a predetermined rolling reduction in a range of T1 + 30 ° C to T1 + 200 ° C, recrystallization is suppressed. In addition, in a case where the waiting time t (seconds) does not satisfy formula 2, the grains are coalesced for the time being very long, and sufficient local deformation capacity cannot be obtained.
    [00173] The cooling pattern after lamination is not particularly limited. The effects of the present invention can be obtained by using a cooling pattern to control the structure according to the respective objectives.
    [00174] During hot rolling, a bar for sheet production can be tied through rough rolling, and finishing lamination can be performed continuously. At that time, a raw bar can be rolled once in the form of a coil, stored in a cover having a heat retention function if necessary, and rolled again, with which the raw bar is tied.
    [00175] In addition, lamination can be performed after hot lamination.
    [00176] A skin pass lamination can be performed on the hot-rolled steel plate as needed. The skin pass lamination has the effect of avoiding the stretching tension that occurs during forming or leveling work. [00177] The structure of the hot-rolled steel sheet obtained in
    Petition 870190036901, of 4/17/2019, p. 52/170
    50/121 configuration includes mainly ferrite, but can include perlite, bainite, martensite, austenite, and compounds such as carbonitrides, such as metal structures other than ferrite. Since the structure of the martensite or bainite crystal is the same or similar to the structure of the ferrite crystal, the above structures may be a major component instead of ferrite.
    [00178] In addition, the steel sheet according to the present invention can be applied not only to folding work, but also to the combined forming mainly composed of folding, super-aging, stamping, and folding work.
    [00179] Next, the method of producing a cold rolled steel sheet according to the configuration will be described. To achieve an excellent local deformation capacity on a steel plate that has undergone cold rolling, it is important to form a texture that has a predetermined random X-ray intensity ratio, satisfies the conditions of the r values in the respective directions, and controls the grain shapes. Details of the production conditions to satisfy the above will be described below.
    [00180] The method of producing hot rolling is not particularly limited. That is, subsequent to casting using a blast furnace, an electric oven, or the like, a variety of secondary purifications are performed, so the ingot can be cast using a method such as a common continuous casting, a casting method, or casting of thin slabs. In the case of continuous casting, the ingot can be cooled once to a low temperature, reheated and then hot rolled, or a cast plate can also be hot rolled in the state after casting without cooling the cast plate to a low temperature. Scrap can be used as raw material.
    Petition 870190036901, of 4/17/2019, p. 53/170
    51/121 [00181] The cold rolled steel sheet having excellent local deformation capacity according to the configuration is obtained in a case in which the following conditions are met.
    [00182] For rC and r30 to satisfy the predetermined values above, the austenite grain diameter after roughing lamination, that is, before finishing lamination, is important. As shown in FIGS. 28 and 29, the grain diameter of the austenite before the finishing lamination is desirably small, and the above values are satisfied when the diameter of the austenite grain is 200 pm or less.
    [00183] To obtain an austenite grain diameter before finishing laminating of 200 pm or less, as shown in FIG. 21, it is necessary to perform roughing lamination in a temperature range of 1000 ° C to 1200 ° C and to perform lamination once or more at a lamination reduction ratio of at least 20% or more. as the lamination reduction ratio and the number of lamination times increase, smaller grains can be obtained. [00184] The austenite grain diameter is most desirably set to 100 pm or less, and in order to reach the austenite grain diameter of 100 pm or less, it is desirable to perform lamination twice or more at a rate of reduction of lamination of 20% or more. Desirably, lamination is performed twice or more at a lamination reduction ratio of 40% or more. As the lamination reduction ratio and the number of lamination times increase, smaller grains can be obtained, but there is a concern that the temperature may decrease or the scalps may be excessively generated when the lamination reduction exceeds 70% or the number of times for roughing rolling exceeds 10 times. As such, a decrease in the grain diameter of the austenite before the finishing lamination is effective in improving the deposition ability 870190036901, from 17/04/2019, p. 54/170
    52/121 local formation by accelerating the recrystallization of austenite during the subsequent finishing lamination, particularly through the control of rL or r30.
    [00185] The reason why the refining of the austenite grain diameter has an influence on the local deformation capacity is supposed to be that the edges of the austenite grains after roughing lamination, that is, the edges of the austenite grains before lamination finishing, works as one of the recrystallization cores during the finishing lamination. In order to confirm the diameter of the austenite grain after roughing lamination, it is desirable to cool the sheet part that is about to undergo the finishing lamination as quickly as possible. The plate piece is cooled at a cooling rate of 10 ° C / s or more, the structure in the cross section of the plate piece is etched, the edges of the austenite grains are shown, and the austenite grain diameter is measured using an optical microscope. At that time, the diameter of the austenite grain is measured at a magnification of 50 times or more in 20 locations or more through an image analysis or by the method of counting points.
    [00186] In addition, to achieve an average value of the random X-ray intensity ratio of the guidance group {100} <011> to {223} <110> in a central portion of the thickness that is in a range of thickness of the plate from 5/8 to 3/8 from the surface of the steel plate, and a random X-ray intensity ratio of the crystal orientation {332} <113> in the above value ranges, based on the T1 temperature determined by steel sheet components in the finishing lamination after roughing lamination, the work is carried out at a high rate of rolling reduction in a temperature range of T1 + 30 ° C to T1 + 200 ° C, desirably in a range of temperatures from T1 + 50 ° C to T1 + 100 ° C, and the work is carried out 870190036901, from 04/17/2019, p. 55/170
    53/121 to a small lamination reduction ratio in a temperature range from T1 ° C to less than T1 + 30 ° C. According to the above, the local deformation capacity and the shape of a hot rolled final product can be guaranteed. FIGS. 30 to 31 show the relationship between the lamination reduction ratios in the temperature range from T1 + 30 ° C to T1 + 200 ° C and the random intensity ratios of the respective guidelines.
    [00187] That is, a large reduction in a temperature range from T1 + 30 ° C to T1 + 200 ° C and the subsequent light lamination at T1 + 30 ° C as shown in FIGS. 30 and 31 control the average value of the random X-ray intensity ratio of the guidance group {100} <011> to {223} <110> in a central portion of the thickness that is in a plate thickness range of 5 / 8 to 3/8 from the surface of the steel plate, and the random X-ray intensity ratio of the crystal orientation {332} <113> in order to dramatically improve the local deformation capacity of the hot-rolled end product as shown in Tables 7 and 8 below. The T1 temperature is obtained experimentally, and the inventors have discovered from the experiments that the recrystallization in the austenite range of the respective steels is accelerated with the T1 temperature as a base.
    [00188] In addition, in order to obtain a more favorable local deformation capacity, it is important to accumulate stress through the large reduction, and the ratio of total lamination reduction is 50% or more, more desirably 60% or more, and even more desirably 70% or more. On the other hand, a total lamination reduction ratio exceeding 90% is not desirable from the point of view of guaranteeing excessive lamination temperatures or loads. In addition, to increase the homogeneity of a hot-rolled sheet, and to increase the local deformation capacity to the extreme, between the rolling passes in a temperature range from T1 + 30 ° C to T1 + 200 ° C, at least
    Petition 870190036901, of 4/17/2019, p. 56/170
    54/121 minus one pass, lamination is performed at a lamination reduction ratio of 30% or more, and desirably 40% or more. Meanwhile, when the lamination reduction ratio exceeds 70% in one pass, there is a concern that the shape may be impaired. In the event that there is a demand for more favorable working conditions, a rolling reduction rate to 30% or more in the last two stages is desirable.
    [00189] Furthermore, in order to accelerate uniform recrystallization by releasing accumulated tension, it is necessary to suppress as much as possible the amount of work in a temperature range of T1 ° C to less than T1 + 30 ° C after the large reduction to T1 + 30 ° C to T1 + 200 ° C, and the total lamination rate at T1 ° C unless T 1 + 30 ° C is adjusted to less than 30%. A lamination reduction ratio of 10% or more is desirable from the point of view of the sheet shape, but a lamination reduction ratio of 0% is desirable in a case where the local deformation capacity matters most. When the lamination reduction ratio at T1 ° C unless T1 + 30 ° C exceeds a predetermined range, the recrystallized austenite grains are expanded, and when the retention time is short, recrystallization does not proceed sufficiently, and local deformation capacity deteriorates. That is, in production conditions depending on the configuration, it is important to uniformly and finely recrystallize austenite during finishing lamination in order to control the texture of a hot rolled product to improve the local deformation capacity so that the expansion properties hole or folding properties.
    [00190] When lamination is performed at a temperature lower than the temperature range specified above or at a lamination reduction ratio greater than the specified lamination reduction ratio, the austenite texture develops and the inPetition ratios 870190036901 , of 17/04/2019, p. 57/170
    55/121 random X-ray tension in the respective crystal orientations, such as the average value of the random X-ray intensity ratio of the orientation group {100} <011> to {223} <110> at least in a central portion the thickness that is in a range of the plate thickness from 5/8 to 3/8 from the surface of the steel plate of less than 4.0 and the x-ray intensity ratio of the crystal orientation {332} <113 > 5.0 or less, cannot be obtained on the finally obtained cold-rolled steel sheet.
    [00191] Meanwhile, when lamination is carried out at a temperature higher than the specified temperature range or at a lower lamination reduction ratio than the specified lamination reduction ratio, the grain will coalesce or the duplex grains, and the area fraction of the crystal grains having a grain diameter of more than 20 pm increases. Whether the lamination specified above is performed or not can be determined from the lamination reduction ratio, the lamination load, the measurement of the sheet thickness, or similar through the current calculation performance. In addition, since the temperature can also be measured if a thermometer is present between the chairs, and the calculation simulation in which the heat generation work and the like are considered from the line speed, the reduction ratio of lamination, and the like is available, whether the lamination specified above is performed or cannot be determined using one or both between temperature and calculation simulation.
    [00192] The hot lamination performed in the above way ends at a temperature of Ar3 or more. When the final temperature of the hot rolling is less than Ar3, since a rolling in a two-phase region in an austenite area and a ferrite area is included, the accumulation in the {100} <011> guidance group a {223} <110> becomes strong and, consequently, capacity 870190036901, of 17/04/2019, p. 58/170
    56/121 of local deformation degrades significantly.
    [00193] As long as rL and r60 are 0.70 or more and 1.10 or less respectively, in addition, a favorable minimum sheet thickness / bending ratio is greater than or equal to 2.0 is satisfied. To achieve a minimum sheet thickness / bending radius ratio greater than or equal to 2.0, the increase in the temperature of the steel sheet between the respective passes during rolling at T1 + 30 ° C to T1 + 200 ° C is desirably suppressed to 18 ° C or less, and it is desirable to employ cooling between chairs, or similar.
    [00194] In addition, the cooling after lamination in the laminator's final lamination chair in a temperature range from T1 + 30 ° C to T1 + 200 ° C has a strong influence on the grain diameter of the austenite, which has an influence strong in the proportion of the equiaxial grain and in the proportion of raw grain of a cold rolled and annealed structure. Therefore, in a case where a pass in which the lamination reduction ratio is 30% or more in a temperature range from T1 + 30 ° C to T1 + 200 ° C is defined as the large reduction pass, it is necessary that the waiting time t from the end of the final pass of the large reduction pass to the start of cooling satisfies formula 4. When the time is too long, the grains are coalesced and the elongation degrades significantly. When the time is too short, recrystallization does not take place and sufficient local deformation capacity cannot be obtained. Therefore, it is not possible for the sheet thickness / minimum bending radius ratio to be greater than or equal to 2.0.
    [00195] In addition, the cooling pattern after hot rolling is not particularly specified, and the effects of the present invention can be obtained by using a cooling pattern to control the structure according to the respective objectives.
    [00196] During hot rolling, a bar for producing
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    57/121 plates can be tied after roughing lamination, and finishing lamination can be carried out continuously. At that time, a raw bar can be rolled once in the form of a coil, stored in a cover having a heat retention function as needed, and rolled again, with which the raw bar is tied.
    [00197] On the steel sheet for which the hot rolling was completed, the cold rolling is performed at a reduction and rolling ratio of 20% to 90%. At a lamination reduction ratio of less than 20%, it becomes difficult to cause recrystallization in a subsequent annealing process, and the annealed crystal grains are coalesced and the proportion of equiaxial grains decreases. At a reduction rate of more than 90%, since the texture develops during annealing, the anisotropy becomes strong. Therefore, the lamination reduction ratio is adjusted to 20% to 90% in cold rolling.
    [00198] The cold-rolled steel sheet is then kept in a temperature range of 720 ° C to 900 ° C for 1 second to 300 seconds. When the temperature is less than 720 ° C or the retention time is less than 1 second, the reverse transformation does not happen sufficiently, at a low temperature or for a short time, and the second phase cannot be achieved in a cooling process. subsequent, and therefore sufficient strength cannot be obtained. On the other hand, when the temperature exceeds 900 ° C or the cold rolled steel sheet is held for 300 seconds or more, the crystal grains coalesce, and so the fraction of area two crystal grains that have a grain diameter of 20 pm or less increases. Thereafter, the temperature is lowered to 500 ° C or less at a cooling rate of 10 ° C / s to 200 ° C / s from 650 ° C to 500 ° C. When the cooling rate is less than 10 ° C / s or cooling ends at a
    Petition 870190036901, of 4/17/2019, p. 60/170
    58/121 temperature above 500 ° C, perlite is generated, and therefore the local deformation capacity degrades. On the other hand, even when the cooling rate is adjusted to more than 200 ° C / s, the perlite suppression effect is saturated, and conversely, the ability to control the cooling end temperature deteriorates significantly, and thus cooling rate is set to 200 ° C / s or less.
    [00199] The structure of the cold rolled steel sheet obtained in the configuration includes ferrite, but can include perlite, bainite, martensite, austenite and compounds such as carbonitrides, as metallic structures other than ferrite. However, since the perlite deteriorates the local deformation capacity, the perlite content is desirably 5% or less. Since the crystal structure of martensite or bainite is the same as or similar to the crystal structure of ferrite, the structure can mainly include any one between ferrite, bainite or martensite.
    [00200] In addition, the cold rolled steel sheet according to the present invention can be applied not only in folding work, but also for combined forming mainly composed of folding, super-aging, stamping, and folding work.
    [00201] Next, the method of producing a galvanized steel sheet according to the configuration will be described.
    [00202] To achieve an excellent local deformation capacity, on a steel plate that has undergone a galvanizing treatment, it is important to form a texture having a predetermined random X-ray intensity ratio, satisfy the conditions of the r values in the respective directions .. Details of the production conditions to satisfy the above will be described below. [00203] The production method that precedes hot rolling
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    59/121 is not particularly limited. That is, subsequent to the casting using a blast furnace, an electric oven, or the like, a variety of secondary purifications are performed, so the ingot can be cast using a method, such as a common continuous casting, a casting method conventional, or thin plate casting. In the case of continuous casting, the ingot can be cooled once to a low temperature, reheated, and then hot rolled, or a cast plate can also be hot rolled in the state after casting without cooling the cast plate to a low temperature. . Scrap can be used as raw material.
    [00204] A galvanized steel sheet having an excellent local deformation capacity as the configuration is obtained in, a case in which the following conditions are satisfied.
    [00205] Initially, for rC and r30 to satisfy the predetermined values above, the diameter of the austenite grains after roughing lamination, that is, before finishing lamination is important. As shown in FIGS. 32 and 33, the austenite grain diameter before the finishing lamination is desirably small, and the above values are satisfied when the austenite grain diameter is 200 pm or less.
    [00206] To obtain an austenite grain diameter before finishing laminating of 200 pm or less, as shown in FIG. 21, it is necessary to perform the roughing lamination in a temperature range of 1000 ° C to 1200 ° C and to perform the lamination one or more times at a lamination reduction ratio of at least 20% or more. However, in order to also increase homogeneity and increase elongation and local deformation capacity, it is desirable to perform lamination once or more at a lamination reduction ratio of at least 40% in terms of a reduction ratio 870190036901, of 17 / 04/2019, p. 62/170
    60/121 tion of rough rolling in a temperature range of 1000 ° C to 1200 ° C.
    [00207] To obtain austenite grains of 100 pm or less which are more preferable, one or more times of lamination, a total of two or more times of lamination at a lamination reduction ratio of 20% or more is also performed. Desirably, lamination is performed twice or more at 40% or more. as the reduction ratio and the number of lamination times increase, smaller grains can be obtained, but there is a concern that the temperature may decrease or scale may be generated excessively when the lamination exceeds 70% or the number of times the roughing lamination exceeds 10 times. As such, a decrease in the diameter of the austenite grain before the finishing lamination is effective in improving the local deformation capacity by accelerating the recrystallization of austenite during the subsequent finishing lamination, particularly through the control of rL or r30.
    [00208] The reason why refining the austenite grain diameter has an influence on the local deformation capacity is supposed to be that the edges of the austenite grains after roughing lamination, that is, the edges of the austenite grains before lamination finishing, work as one of the recrystallization cores during the finishing lamination.
    [00209] In order to confirm the austenite grain diameter after roughing lamination, it is desirable to cool the sheet skin that is about to undergo the finishing lamination as quickly as possible. The plate piece is cooled at a cooling rate of 10 ° C / s or more, the structure in the cross section of the plate piece is etched, the edges of the austenite grains are shown, and the diameter of the austenite grains is measured using an optical microscope. At that time, the diameter of the austenite grain is measured at
    Petition 870190036901, of 4/17/2019, p. 63/170
    61/121 an enlargement of 50 times or more in 20 locations or more through an image analysis or a method of counting points. In addition, the diameter of the austenite grain is desirably 100 pm or less to increase local deformation capacity.
    [00210] In addition, to achieve an average value of the random X-ray intensity ratio of the guidance group {100} <011> to {223} <110> in a central portion of the thickness that is in a range of 5 / 8 to 3/8 from the plate surface and the random X-ray intensity ratio of the crystal orientation {332} <113> in the above value ranges, based on the T1 temperature determined by the steel plate components specified in formula 1 in finishing lamination after roughing lamination, the work is carried out at a high rate of lamination reduction in a temperature range from T1 + 30 ° C to T1 + 200 ° C, desirably in a temperature range of T1 + 50 ° C to T1 + 100 ° C, and work is performed at a small rate of lamination reduction in a temperature range from T1 ° C to less than T1 + 30 ° C. According to the above, the local deformation capacity and the shape of a hot rolled end product can be guaranteed.
    [00211] FIGS. 34 to 37 show the relationship between the lamination reduction ratios in the respective temperature ranges and the random X-ray intensity ratios of the respective guidelines. [00212] That is, a large reduction at a total reduction ratio of 50% or more over a temperature range from T1 + 30 ° C to T1 + 200 ° C as shown in FIGS. 34 and 36 and the subsequent lamination leads to a total lamination reduction ratio of less than 30% or more at T1 ° C to less than T1 + 30 ° C as shown in FIGS. 35 to 37 control the average value of the random X-ray intensity ratio of the guidance group {100} <011> to {223} <110> in a central portion of the thickness that is in a plate thickness range
    Petition 870190036901, of 4/17/2019, p. 64/170
    62/121 from 5/8 to 3/8 from the steel plate surface, and the random X-ray intensity ratio of the crystal orientation {332} <113> in order to dramatically improve the local deformation capacity of the hot rolled end product. The T1 temperature is obtained experimentally, and the inventors discovered, through experiments, that the recrystallization in the austenite range of the respective steels is accelerated with the T1 temperature as a base.
    [00213] In addition, in order to obtain a more favorable local deformation capacity, it is important to accumulate tension through a great reduction in or repeatedly recrystallize the structure with each lamination. For stress build-up, the lamination reduction ratio needs to be 50% or more, more desirably 60% or more, and even more desirably 70% or more, and the increase in temperature of the steel sheet between passes is desirably 18 ° C or less. On the other hand, achieving a lamination reduction ratio of more than 90% is not desirable from the point of view of guaranteeing the temperature or excessive lamination load. In addition, to increase the homogeneity of a hot-rolled sheet, and increase the local deformation capacity to the extreme, between the rolling passes in a temperature range from T1 + 30 ° C to T1 + 200 ° C, at least minus one pass, lamination is performed at a lamination reduction rate of 30% or more, and desirably 40% or more. Meanwhile, when the lamination reduction ratio exceeds 70% in one pass, there is a concern that the shape may be impaired. In a case where there is a demand for a more favorable work capacity, it is more desirable to adjust the lamination reduction ratio to 30% or more at the end of 2 passes.
    [00214] Furthermore, in order to accelerate uniform recrystallization by releasing accumulated tension, it is necessary to suppress as much as possible the amount of work in a temperature range of
    Petition 870190036901, of 4/17/2019, p. 65/170
    63/121
    T1 ° C less than T1 + 30 ° C after the large reduction at T1 + 30 ° C to T1 + 200 ° C, and the total lamination rate at T1 ° C less than T1 + 30 ° C is adjusted to less 30%. A lamination reduction rate of 10% or more is desirable from the point of view of the sheet shape, but a lamination reduction rate of 0% is desirable in a case where the local deformation capacity is focused. When the lamination reduction ratio at T1 ° C to less than T1 + 30 ° C exceeds a predetermined range, recrystallized austenite grains are expanded, and when the retention time is short, recrystallization does not occur sufficiently, and the capacity local deformation deteriorates. That is, in production conditions according to the configuration, it is important to finely and uniformly recrystallize austenite during the finishing lamination in order to control the texture of a hot rolled product to improve the local deformation capacity, as well as expansion properties of hole or folding properties.
    [00215] When lamination is carried out at a temperature less than the temperature range specified above or at a lamination reduction ratio less than the specified lamination reduction ratio, the austenite texture develops, and the random intensity ratios of X-rays in the respective crystal orientations, such as the average value of the random X-ray intensity ratio of the orientation group {100} <011> to {223} <110> at least in a central portion of the thickness that is in a plate thickness range of 5/8 to 3/8 from the plate surface of less than 4.0, and a random X-ray intensity ratio of the {332} <113> crystal orientation of 5.0 or at least, it cannot be obtained in the finally obtained galvanized steel sheet. Meanwhile, when lamination is performed at a temperature higher than the specified temperature range or at a lamination reduction ratio less than the
    Petition 870190036901, of 4/17/2019, p. 66/170
    64/121 lamination reduction ratio specified, results in the coalescence of the grains or the duplex grain and, consequently, the local deformation capacity degrades significantly. Whether the lamination specified above is carried out or not can be determined from the lamination reduction ratio, the lamination load, the measurement of sheet thickness, etc., through actual performance or calculation. In addition, since the temperature can also be measured if a thermometer is present between the chairs, and the calculation simulation in which the heat generation work and the like are considered based on the line speed, the reduction ratio of lamination, etc. is available, whether the lamination specified above is performed or cannot be determined using one or both between the temperature and the calculation simulation.
    [00216] The hot lamination performed in the above way ends at a temperature of Ar3 or higher. When the hot rolling end temperature is less than Ar3, since a two-phase rolling in an austenite area and a ferrite area is included, the accumulation in the {100} <011> guidance group a {223} <110> becomes strong and, consequently, the local deformation capacity degrades significantly.
    [00217] Furthermore, since rL and r60 are 0.70 or more and 1.10 or less respectively, in addition, the ratio of sheet thickness / minimum bending radius is greater than or equal to 2.0. To achieve the minimum sheet thickness / bending radius ratio greater than or equal to 2.0. in a case where a pass in which the lamination reduction ratio is 30% or more in a temperature range from T1 + 30 ° C to T1 + 200 ° C is defined as the high reduction pass, it is important that the waiting time t (seconds) from the end of the final pass of the high reduction pass until the beginning of the cooling process satisfies formula 6.
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    65/121 [00218] FIGS. 38 and 39 show the relationship between the increase in the temperature of the steel sheet during rolling at T1 + 30 ° C to T1 + 200 ° C, the waiting time t, rL, and r60.
    [00219] The waiting time t that satisfies formula 6 and, in addition, the suppression of the increase in the temperature of the steel sheet at T1 + 30 ° C to T1 + 200 ° C at 18 ° C or less in the respective passes are effective to obtain uniformly recrystallized austenite.
    [00220] Furthermore, in a case where the temperature increase at T1 + 30 ° C to T1 + 200 ° C is very low so that the predetermined lamination reduction ratio cannot be obtained in a range of T1 + 30 ° C to T1 + 200 ° C, recrystallization is suppressed and, in a case where the waiting time t does not satisfy formula 6, because the time is very long, the beans are coalesced and, for the time being too short, recrystallization does not take place and sufficient local deformation capacity cannot be achieved.
    [00221] The cooling pattern after hot rolling is not particularly specified, and the effects of the present invention can be obtained by using a cooling pattern to control the structure according to the respective objectives. However, when the winding temperature exceeds 680 ° C, since there is a concern that surface oxidation may occur or the bending properties after cold rolling or annealing may be adversely influenced, the winding temperature is adjusted to a temperature from room temperature to 680 ° C.
    [00222] During hot rolling, a bar for sheet production can be attached after roughing rolling, and finishing rolling can be performed continuously. At that time, a raw bar can be rolled once in the form of a coil, stored in a cover having a heat retention function
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    66/121 as needed, and laminated again, with which the raw bar is tied. Skin pass lamination can be performed on hot-rolled steel plate as needed. The skin pass lamination has the effect of avoiding the stretching tension that occurs during forming work or planing correction.
    [00223] In addition, the steel sheet for which the hot rolling was completed is subjected to pickling, and then cold rolling to a rolling reduction ratio of 20% to 90%. When the lamination reduction ratio is less than 20%, there is a concern that sufficient cold-rolled recrystallized structures cannot be formed, and mixed grains can be formed. In addition, when the lamination reduction ratio exceeds 90%, there is a concern for breakage due to cracking. The effects of the present invention can be obtained even when the heat treatment pattern to control the structure according to the purposes is employed as the annealing heat treatment pattern [00224] However, to obtain a sufficient cold rolled recrystallized equiaxial structure and satisfy conditions in the ranges of the present application, it is necessary to heat the steel sheet to a temperature range of at least 650 ° C to 900 ° C, anneal the steel sheet for a retention time of 1 second to 300 seconds, and then execute primary cooling to a temperature range of 720 ° C to 580 ° C at a cooling rate of 0.1 ° C / s to 100 ° C / s. When the holding temperature is less than 650 ° C, or the holding time is less than 1 second, a sufficiently recovered recrystallized structure cannot be obtained. In addition, when the holding temperature exceeds 900 ° C, or the holding time exceeds 300 seconds, there is a concern for oxidation or coalescence of the grains. In addition, when the cooling rate is less than 0.1 ° C / s or the temperature range exceeds 720 ° C in temporary cooling, there is the
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    67/121 concern that a sufficient amount of transformation cannot be achieved. In addition, in a case where the cooling rate exceeds 100 ° C / s, or the temperature range is less than 580 ° C, there is a concern for grain coalescence or the like. [00225] After this, according to a common method, a galvanizing treatment is carried out in order to obtain a galvanized steel sheet.
    [00226] The structure of the galvanized steel sheet obtained in the configuration includes mainly ferrite, but can include perlite, bainite, martensite, austenite, and compounds such as carbonitrides, as metallic structures other than ferrite. Since the crystal structure of martensite or bainite is the same as, or similar to, the crystal structure of ferrite, the structure can mainly include anyone between ferrite, bainite and martensite.
    The galvanized steel sheet according to the present invention can be applied not only to the folding work, but also to the combined forming mainly composed of folding, super-aging, stamping and folding work. [EXAMPLE 1] [00227] The technical content of the steel sheet according to the configuration will be described using examples of the present invention.
    [00228] The results of the studies in which AB to Bg steels were used having the component compositions shown in Table 1
    Petition 870190036901, of 4/17/2019, p. 70/170 [TABLE 1]
    Table 1 - Chemical components (% by mass) - 1/4
    T1 / ° C Ç Si Mn P s Al N O You Nb AB 865 0.080 0.31 1.35 0.012 0.005 0.016 0.0032 0.0023 - 0.041 B.C 858 0.060 0.87 1.20 0.009 0.004 0.038 0.0033 0.0026 - 0.021 AD 865 0.210 0.15 1.62 0.012 0.003 0.026 0.0033 0.0021 0.021 - AE 861 0.035 0.67 1.88 0.015 0.003 0.045 0.0028 0.0029 - 0.021 AF 875 0.180 0.48 2.72 0.009 0.003 0.050 0.0036 0.0022 - - AG 892 0.060 0.11 2.12 0.010 0.005 0.033 0.0028 0.0035 0.036 0.089 AH 903 0.040 0.13 1.33 0.010 0.005 0.038 0.0032 0.0026 0.042 0.121 THERE 855 0.350 0.52 1.33 0.260 0.003 0.045 0.0026 0.0019 - - AJ 1376 0.072 0.15 1.42 0.014 0.004 0.036 0.0022 0.0025 - 15 AK 851 0.110 0.23 1.12 0.021 0.003 0.026 0.0025 0.0023 - - AL 1154 0.250 0.23 1.56 0.024 0.120 0.034 0.0022 0.0023 - - BA 864 0.078 0.82 2.05 0.012 0.004 0.032 0.0026 0.0032 0.02 0.02 BB 852 0.085 0.75 2.25 0.012 0.003 0.035 0.0032 0.0023 - - BC 866 0.110 0.10 1.55 0.02 0.004 0.038 0.0033 0.0026 - 0.04 BD 863 0.350 1.80 2.33 0.012 0.003 0.710 0.0033 0.0021 0.02 BE 859 0.120 0.22 1.35 0.015 0.003 0.025 0.0055 0.0029 - 0.02 BF 884 0.068 0.50 3.20 0.122 0.002 0.040 0.0032 0.0038 0.03 0.07 BG 858 0.130 0.24 1.54 0.010 0.001 0.038 0.0025 0.0029 - 0.02
    68/121
    Petition 870190036901, of 4/17/2019, p. 71/170
    T1 / ° C Ç Si Mn P s Al N O You Nb BH 899 0.035 0.05 2.20 0.010 0.020 0.021 0.0019 0.0023 0.15 0.03 BK 861 0.144 0.45 2.52 0.007 0.001 0.021 0.0024 0.0031 0.03 -
    Table 1 - Chemical components (% by mass) - 2/4
    B Mg Landsrare Here Mo Cr W At V Others Note AB - - - - - - - - - - Invention steel B.C - - 0.002 - - - - - - - Invention steel AD 0.0022 - - - 0.03 0.35 - - - - Invention steel AE - 0.002 - 0.002 - - - - 0.03 - Invention steel AF - 0.002 - - 0.10 - - - 0.10 - Invention steel AG 0.0012 - - - - - - - - - Invention steel AH 0.0009 - - - - - - - - - Invention steel THERE - - - - - - - - - - Comparative steel AJ - - - - - - - - - - Comparative steel AK - 0.150 - - - - - - - - Comparative steel AL - - - - - 5.0 - - 2.50 - Comparative steel BA - - - - - - - - - - Invention steel BB - - - - - - - - - Co: 0.5%Sn: 0.02% Invention steel BC - - - - - - - - - - Invention steel
    69/121
    Petition 870190036901, of 4/17/2019, p. 72/170
    B Mg Landsrare Here Mo Cr W At V Others Note BD 0.0020 - 0.004 - - - - - - - Invention steel BE - - - - - - - - - - Invention steel BF - - 0.004 - - 0.10 - - - - Invention steel BG - - - - - - - - - Invention steel BH - - 5E-04 9E-04 0.1 - - Invention steel BK - - - - - - - - - Cu: 0.5%,Ni: 0.25%,Zr: 0.02% Invention steel
    Table 1 - Chemical components (% by mass) - 3/4
    70/121
    T1 / ° C Ç Si Mn P s Al N O You Nb BL 853 0.190 1.40 1.78 0.011 0.002 0.018 0.0032 0.0028 - - BM 866 0.080 0.10 1.40 0.007 0.002 1,700 0.0033 0.0034 - - BO 885 0.120 0.80 2.20 0.008 0.002 0.035 0.0022 0.0035 0.05 - BP 873 0.190 0.55 2.77 0.009 0.002 0.032 0.0033 0.0036 0.04 - BQ 852 0.082 0.77 1.82 0.008 0.003 0.025 0.0032 0.0031 - - BR 875 0.030 1.00 2.40 0.005 0.001 0.033 0.0022 0.0011 0.05 0.01 BT 861 0.142 0.70 2.44 0.008 0.002 0.030 0.0032 0.0035 0.03 - BU 876 0.009 0.10 1.40 0.006 0.001 0.003 0.0033 0.0024 0.10 - BV 853 0.150 0.61 2.20 0.011 0.002 0.028 0.0021 0.0036 - -
    Petition 870190036901, of 4/17/2019, p. 73/170
    T1 / ° C Ç Si Mn P s Al N O You Nb BW 1043 0.120 0.17 2.26 0.028 0.009 0.033 0.0027 0.0019 - - Ba 860 0.440 0.50 2.20 0.008 0.002 0.035 0.0021 0.0012 - - Bb 854 0.080 0.45 4.50 0.200 0.002 0.034 0.0041 0.0015 - - Bc 914 0.080 0.35 2.00 0.008 0.002 0.033 0.0042 0.0034 0.25 - Bd 939 0.070 0.35 2.40 0.008 0.002 0.035 0.0035 0.0026 - 0.25 Be 851 0.090 0.10 1.00 0.008 0.040 0.036 0.0035 0.0022 - - Bf 952 0.070 0.21 2.20 0.008 0.002 0.033 0.0023 0.0036 - - Bg 853 0.140 0.11 1.90 0.008 0.002 0.032 0.0044 0.0035 - -
    Table 1 - Chemical components (% by mass) - 4/4
    B Mg Landsrare Here Mo Cr W At V Others Note BL 0.0002 - - - - - - - - - Invention steel BM - - - 0.002 - - - - 0.15 - Invention steel BO - - - - - - - 0 0.20 - Invention steel BP - 0.006 - - 0.02 - - - 0.05 - Invention steel BQ 0.0002 - - - - - - - - - Invention steel BR - 0.004 0.004 - - 0.80 - - - - Invention steel BT 0.0002 - - - - - - - - - Invention steel BU - - - - 0.01 - - - - - Invention steel BV - 0.004 0.005 - - - - - - - Invention steel
    71/121
    Petition 870190036901, of 4/17/2019, p. 74/170
    B Mg Landsrare Here Mo Cr W At V Others Note BW - - - - 0.90 - - - - - Invention steel Ba - - - - - - - - - - Comparative steel Bb - - - - - - - - - - Comparative steel Bc - - - - - - - - - - Comparative steel Bd - - - - - - - - - - Comparative steel Be - - - - - - - - - - Comparative steel Bf - 0.020 - - - - - - 1.10 - Comparative steel Bg - - 0.15 - - - - - - - Comparative steel
    [00229] The steels were cast, reheated in the state or after being cooled to room temperature, heated to a temperature range of 900 ° C to 1300 ° C, and then hot rolled under the conditions of Tables 2 and 3, obtaining thus, finally, hot-rolled steel sheets with a thickness of 2.3 mm or 3.2 mm.
    72/121
    Petition 870190036901, of 4/17/2019, p. 75/170 [TABLE 2]
    Table 2 - Production conditions - 1/2
    Steel type T1 / ° C Lamination times of 20% or more at1000 ° C to 1200 ° C Lamination reduction rate of 20% or more at 1000 ° C at1200 ° C /% Austenite grain diameter / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Temperature increase during lamination at T1 + 30 ° C to T1 + 200 ° C / ° C 3 AB 865 2 45/45 80 75 15 4 AB 865 2 45/45 80 85 18 5 B.C 858 2 45/45 95 85 13 6 B.C 858 2 45/45 95 95 14 7 AD 862 3 40/40/40 75 80 16 8 AE 858 2 45/40 95 80 17 9 AE 858 1 50 120 80 18 10 AF 875 3 40/40/40 70 95 18 11 AG 892 3 40/40/40 65 95 10 12 AH 903 2 45/45 70 90 13 13 AH 903 2 45/45 95 85 15 14 AF 875 3 40/40/40 70 65 20 15 AG 892 1 50 120 75 20 16 AG 892 1 50 120 60 21 17 AH 903 1 50 120 65 19
    73/121
    Petition 870190036901, of 4/17/2019, p. 76/170
    Steel type T1 / ° C Lamination times of 20% or more at1000 ° C to 1200 ° C Lamination reduction rate of 20% or more at 1000 ° C at1200 ° C /% Austenite grain diameter / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Temperature increase during lamination at T1 + 30 ° C to T1 + 200 ° C / ° C 18 AH 903 1 50 120 35 12 20 AB 865 2 45/45 80 45 15 21 AV 858 2 40/45 95 75 12 22 AG 892 0 - 350 45 30 23 AE 858 1 50 120 80 40 25 B.C 858 0 - 300 85 13 26 THERE 855 Cracked during hot rolling 27 AJ 1376 Cracked during hot rolling 28 AK 851 Cracked during hot rolling 29 AL 1154 Cracked during hot rolling
    74/121
    Petition 870190036901, of 4/17/2019, p. 77/170
    Table 2 - Production conditions - 2/2
    Steel type Total lamination reduction rate at T1 ° C to less thanT1 + 30 ° C /% Tf: Temperature after the final pass of the heavy rolling pass / ° C P1: Lamination reduction rate of the final pass of the heavy lamination pass /% t1 2.5 x t1 t: Waiting time from the end of the heavy rolling pass to the start of cooling / s t / t1 Winding temperatureto / ° C 1 10 l 40 0.57 1.41 0.8 1.41 600 2 0 892 35 1.74 4.35 2 1.15 50 3 25 945 37 0.76 1.90 1 1.32 600 4 5 920 31 1.54 3.86 2.3 1.49 50 5 15 955 31 0.73 1.82 1 1.38 600 6 0 934 40 0.71 1.78 1 1.41 500 7 25 970 30 0.62 1.56 0.9 1.45 600 8 5 960 30 0.70 1.75 1 1.42 300 9 15 921 30 1.40 3.50 2 1.43 200 10 0 990 30 0.53 1.32 0.7 1.32 500 11 0 943 35 1.46 3.65 2.1 1.44 600 12 0 1012 40 0.25 0.63 0.3 1.19 500 13 10 985 40 0.61 1.52 0.9 1.48 600 14 25 965 34 0.70 1.75 0.9 1.28 500 15 15 993 30 0.71 1.77 0.8 1.13 500 16 20 945 45 1.06 2.64 1.1 1.04 600 17 15 967 38 1.05 2.63 1.5 1.43 500
    75/121
    Petition 870190036901, of 4/17/2019, p. 78/170
    Steel type Total lamination reduction rate at T1 ° C to less thanT1 + 30 ° C /% Tf: Temperature after the final pass of the heavy rolling pass / ° C P1: Lamination reduction rate of the final pass of the heavy lamination pass /% t1 2.5 x t1 t: Waiting time from the end of the heavy rolling pass to the start of cooling / s t / t1 Winding temperatureto / ° C 18 45 880 30 3.92 9.79 5 1.28 100 19 45 930 30 1.08 2.69 5 4.64 600 20 45 1075 30 0.20 0.50 01 0.50 600 21 45 890 30 2.15 5.36 13 0.61 600 22 35 910 35 2.44 6.09 05 0.21 400 23 35 860 40 3.02 7.54 9 2.98 600 24 20 850 30 3.13 7.83 03 0.10 800 25 25 890 30 2.15 5.36 2.2 1.03 600 26 Cracked during hot rolling 27 Cracked during hot rolling 28 Cracked during hot rolling 29 Cracked during hot rolling
    76/121
    Petition 870190036901, of 4/17/2019, p. 79/170 [TABLE 3]
    Table 3 - Production conditions - 1/2
    Steel type T1 / ° C Number of times of lamination at 20% or more at 1000 ° C at1200 ° C Lamination reduction rate at 20% or more at 1000 ° C at1200 ° C /% Austenite grain diameter / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Temperature rise during laminationat T1 + 30 ° C atT1 + 200 ° C / ° C BA1 BA 864 lamination 80 85 17 BB1 BB 852 2 45/45 85 80 13 BB2 BB 852 2 45/45 80 85 16 BC1 BC 866 2 45/45 80 85 16 BD1 BD 863 1 50 120 85 14 BE2 BE 859 2 45/45 80 80 16 BF1 BF 884 2 45/45 75 85 15 BF2 BF 884 1 50 110 80 13 BG1 BG 858 3 40/40/40 80 80 15 BH1 BH 899 2 45/45 80 80 12 BK1 BK 861 3 40/40/40 85 90 13 BK2 BK 853 3 40/40/40 85 90 12 BL1 BL 853 2 45/45 80 85 14 BL2 BL 853 2 45/45 80 80 17 BM1 BM 866 1 30 140 65 12 BO1 BO 885 2 45/45 80 60 15
    77/121
    Petition 870190036901, of 4/17/2019, p. 80/170
    Steel type T1 / ° C Number of times of lamination at 20% or more at 1000 ° C at1200 ° C Lamination reduction rate at 20% or more at 1000 ° C at1200 ° C /% Austenite grain diameter / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Temperature rise during laminationat T1 + 30 ° C atT1 + 200 ° C / ° C BP1 BP 873 2 45/45 75 85 13 BQ1 BQ 852 2 45/45 80 80 16 BR1 BR 875 2 45/45 75 85 12 BT1 BT 861 2 45/45 80 95 16 BT2 BT 861 2 45/45 85 80 12 BU1 BU 876 2 45/45 75 85 12 BV1 BV 853 2 45/45 85 80 11 BW1 BW 1043 1 50 120 80 16 Ba1 Ba 860 2 45/45 75 90 16 Bb1 Bb 854 1 50 120 85 12 Bc1 Bc 914 2 45/45 75 90 13 Bd1 Bd 939 2 45/45 75 85 12 Be1 Be 851 2 45/45 80 65 11 Bf1 Bf 952 2 45/45 80 70 12 Bg1 Bg 853 2 45/45 75 60 12
    78/121
    Petition 870190036901, of 4/17/2019, p. 81/170
    Table 3 - Production conditions - 2/2
    Steel type Total lamination reduction rate at T1 ° C atless thanT1 + 30 ° C /% Tf: Temperature after the final pass of the heavy rolling pass / ° C P1: Lamination reduction rate of the final pass of the heavy lamination pass /% t1 2.5 x t1 t: waiting time from the end of the heavy rolling pass to the start of cooling / s t / t1 Coil temperature-/ ° C BA1 0 984 45 0.13 0.33 0.28 2.15 500 BB1 0 982 40 0.14 0.34 0.29 2.10 500 BB2 0 922 45 0.66 1.65 1.15 1.75 500 BC1 0 966 45 0.22 0.55 0.37 1.68 600 BD1 0 963 40 0.34 0.85 0.49 1.44 600 BE2 0 929 45 0.66 1.65 1.15 1.75 600 BF1 15 944 45 0.89 2.22 1.04 1.17 500 BF2 0 954 40 0.83 2.08 6.00 7.21 500 BG2 0 958 45 0.22 0.55 0.37 1.68 600 BH1 20 959 40 1.06 2.65 1.21 1.14 500 BK1 0 961 40 0.34 0.85 0.49 1.44 550 BK2 0 923 40 0.83 2.08 0.98 1.18 600 BL1 0 953 45 0.22 0.55 0.37 1.68 600 BL2 0 923 50 0.51 1.28 0.66 1.29 600 BM1 10 966 40 0.34 0.85 0.49 1.44 500 BO1 0 985 45 0.22 0.55 0.37 1.68 600 BP1 0 973 40 0.34 0.85 0.49 1.44 600
    79/121
    Petition 870190036901, of 4/17/2019, p. 82/170
    Steel type Total lamination reduction rate at T1 ° C atless thanT1 + 30 ° C /% Tf: Temperature after the final pass of the heavy rolling pass / ° C P1: Lamination reduction rate of the final pass of the heavy lamination pass /% t1 2.5 x t1 t: waiting time from the end of the heavy rolling pass to the start of cooling / s t / t1 Coil temperature-/ ° C BQ1 0 952 45 0.22 0.55 0.37 1.68 600 BR1 0 985 40 0.24 0.60 0.39 1.63 500 BT1 15 961 45 0.22 0.55 0.37 1.68 500 BT2 0 931 40 0.83 2.08 0.98 1.18 500 BU1 10 976 40 0.34 0.85 0.49 1.44 500 BV1 0 953 40 0.34 0.85 0.49 1.44 600 BW1 10 1083 45 1.46 3.66 1.61 1.10 550 Ba1 0 960 45 0.22 0.55 0.37 1.68 600 Bb1 0 954 40 0.34 0.85 0.49 1.44 600 Bc1 0 994 40 0.64 1.59 0.79 1.24 600 Bd1 0 999 40 1.06 2.65 1.21 1.14 600 Be1 0 951 40 0.34 0.85 0.49 1.44 600 Bf1 0 1012 40 1.06 2.65 1.21 1.14 600 Bg1 0 953 40 0.34 0.85 0.49 1.44 600
    80/121
    Petition 870190036901, of 4/17/2019, p. 83/170
    81/121 [00230] Table 1 shows the chemical components of the respective steels, Tables 2 and 3 show the respective production conditions, and Tables 4 and 5 show structures and mechanical characteristics.
    [00231] As an index of local deformation capacity, the hole expansion rate and the bending radius limit through the 90 ° V-shaped bend were used. In the folding tests, the folding in the C direction and the folding in the 45 ° direction were performed, and the rates were used as an index of the dependence on the orientation of the forming capacity. The tensile and bend tests were based on the JIS Z2241 and the 90 ° bend tests of the JIS Z2248 V block, and the hole expansion tests were based on the Japan Iron and Steel Federation standard JFS T1001, respectively . The random X-ray intensity ratio was measured using EBSD at an extreme intensity of 0.5 pm in relation to the location 1/4 from the final portion in the direction of the width in a central portion of the plate thickness in an area 5/8 to 3/8 of a cross section parallel to the rolling direction. In addition, the values in the respective directions were measured using the methods above.
    Petition 870190036901, of 4/17/2019, p. 84/170 [TABLE 4]
    Table 4 - Structures and mechanical characteristics of the respective steels in the respective production conditions (1/2)
    Steel type random X-ray intensity ratio of the guidance group {100} <011> to {223} <110> Random X-ray intensity ratio of {332} <113> rL rC r30 r60 Area ratio of coalesced grain /% 1 2.6 2.2 0.88 0.87 1.04 1.05 5 2 2.2 2.1 0.92 0.90 0.96 0.98 1 3 2.9 2.8 0.87 0.79 1.05 1.05 5 4 2.7 2.7 0.90 0.85 1.02 1.03 4 5 3.5 3.2 0.78 0.75 0.98 1.00 6 6 3.0 2.8 0.83 0.85 0.95 0.98 4 7 5.2 4.1 0.70 0.70 1.08 1.09 7 8 2.9 2.7 0.85 0.90 1.06 1.05 5 9 3.5 2.9 0.75 0.95 1.02 1.10 5 10 3.0 3.0 0.72 0.75 1.05 1.08 6 11 2.9 3.0 0.72 0.74 1.07 1.09 6 12 2.9 2.6 0.71 0.72 1.06 1.08 3 13 3.0 2.9 0.73 0.72 1.10 1.08 5 14 5.4 4.6 0.66 0.73 1.10 1.20 5
    82/121
    Petition 870190036901, of 4/17/2019, p. 85/170
    Steel type random X-ray intensity ratio of the guidance group {100} <011> to {223} <110> Random X-ray intensity ratio of {332} <113> rL rC r30 r60 Area ratio of coalesced grain /% 15 3.7 3.5 0.65 0.75 1.05 1.19 4 16 5.4 4.5 0.58 0.70 1.10 1.26 1 17 5.4 3.0 0.64 0.75 1.02 1.15 5 18 7.2 6.4 0.54 0.67 1.24 1.31 3 19 62 5.1 0.69 0.79 1.15 1.15 29 20 62 5.2 0.56 0.65 1.25 1.19 1 21 72 5.8 0.65 0.68 1.18 1.15 1 22 72 5.4 0.52 0.65 1.22 1.30 1 23 7.1 6.4 0.63 0.65 1.15 1.23 16 24 5.4 5.6 0.59 0.75 1.05 1.21 1 25 5.2 5.4 0.68 0.72 1.15 1.10 4 26 Cracked during hot rolling 27 Cracked during hot rolling 28 Cracked during hot rolling 29 Cracked during hot rolling
    83/121
    Petition 870190036901, of 4/17/2019, p. 86/170
    Table 4 - Structures and mechanical characteristics of the respective steels in the respective production conditions (2/2)
    Steel type equiaxial grain rate /% TS / MPa El./% λ /% TSxA / MPa-% Sheet thickness / bending radiusMinimum Folding ratio in 45 ° direction / folding in C direction Note 1 74 445 34 145 64525 3.2 1.1 Invention steel 2 80 450 38 180 81000 3.3 1.0 Invention steel 3 72 605 25 95 57475 3.2 1.2 Invention steel 4 73 595 24 115 68425 2.3 1.1 Invention steel 5 75 595 29 85 50575 2.7 1.2 Invention steel 6 78 600 28 90 54000 2.3 1.1 Invention steel 7 72 650 19 75 48750 2.1 1.5 Invention steel 8 72 625 21 135 84375 3.3 1.1 Invention steel 9 72 635 19 118 74930 3.2 1.2 Invention steel 10 78 735 15 75 55125 2.5 1.4 Invention steel 11 77 810 19 85 68850 2.3 1.4 Invention steel 12 78 790 21 140 110600 2.7 1.4 Invention steel 13 74 795 20 140 111300 2.3 1.4 Invention steel 14 69 765 14 60 45900 15 1.6 Invention steel 15 74 825 18 70 57750 16 1.5 Invention steel
    84/121
    Petition 870190036901, of 4/17/2019, p. 87/170
    Steel type equiaxial grain rate /% TS / MPa El./% λ /% TSxA / MPa-% Sheet thickness / bending radiusMinimum Folding ratio in 45 ° direction / folding in C direction Note 16 70 835 17 65 54275 1.5 1.8 Invention steel 17 67 830 17 125 103750 1.5 1.5 Invention steel 18 59 805 19 60 48300 1.1 2.0 Comparative Steel 19 29 465 34 85 39525 12 1.5 Comparative Steel 20 70 635 24 65 41275 12 1.9 Comparative Steel 21 79 640 26 45 28800 12 1.7 Comparative Steel 22 73 845 16 45 38025 11 2.0 Comparative Steel 23 57 670 16 75 50250 12 1.8 Comparative Steel 24 81 405 30 70 28350 11 1.6 Comparative Steel 25 78 650 27 50 32500 11 1.5 Comparative Steel 26 Cracked during hot rolling Comparative Steel 27 Cracked during hot rolling Comparative Steel 28 Cracked during hot rolling Comparative Steel 29 Cracked during hot rolling Comparative Steel
    85/121
    Petition 870190036901, of 4/17/2019, p. 88/170 [TABLE 5]
    Table 5 - Structures and mechanical characteristics of the respective steels in the respective production conditions (1/4)
    Steel type Ratio of random intensity of X-rays of the group of orientations {100} <011> to {223} <110> Random X-ray intensity ratio of {332} <113> rL rC r30 r60 Area ratio of coalesced grain /% BA1 2.3 2.4 0.83 0.84 0.85 0.88 9 BB1 2.4 2.4 0.84 0.85 0.86 0.89 9 BB2 2.8 2.8 0.79 0.81 0.90 0.92 6 BC1 2.8 2.9 0.78 0.80 0.91 0.93 6 BD1 3.5 3.1 0.83 0.84 0.99 0.99 5 BE2 2.8 2.8 0.79 0.81 0.90 0.92 6 BF1 3.3 3.4 0.72 0.75 0.97 0.98 2 BF2 1.1 1.2 0.95 0.95 0.99 1.01 30 BG1 2.8 2.8 0.78 0.80 0.91 0.93 6 BH1 3.4 3.4 0.72 0.76 0.97 0.98 2 BK1 3.1 3.2 0.76 0.79 0.95 0.96 5 BK2 3.4 3.4 0.73 0.76 0.99 0.99 3 BL1 2.8 2.9 0.78 0.80 0.91 0.93 6 BL2 3.2 3.2 0.74 0.77 0.95 0.96 2 BM1 3.7 2.9 0.87 0.87 0.99 0.99 5
    86/121
    Petition 870190036901, of 4/17/2019, p. 89/170
    Steel type Ratio of random intensity of X-rays of the group of orientations {100} <011> to {223} <110> Random X-ray intensity ratio of {332} <113> rL rC r30 r60 Area ratio of coalesced grain /% BO1 2.8 2.6 0.78 0.80 0.89 0.91 6 BP1 3.0 3.1 0.74 0.77 0.94 0.95 5
    Table 5 - Structures and mechanical characteristics of the respective steels in the respective production conditions (2/4)
    Steel type Equiaxial grain rate /% TS / MPa El./% λ /% TSxA / MPa-% Sheet thickness / minimum bending radius folding ratio in direction 45 ° - / folding in direction C Note BA1 67 785 24 125 98125 6.4 1.0 Invention steel BB1 66 787 24 123 96801 6.3 1.0 Invention steel BB2 71 777 24 120 93240 5.0 1.1 Invention steel BC1 72 598 28 155 92690 4.8 1.1 Invention steel BD1 74 1216 14 25 30400 4.1 1.1 Invention steel BE2 69 588 29 158 92904 5.0 1.1 Invention steel BF1 77 1198 14 65 77870 3.6 1.3 Invention steel BF2 30 1100 5 50 55000 6.0 1.0 Invention steel BG1 70 594 29 156 92664 4.8 1.1 Invention steel BH1 75 843 20 101 85143 3.6 1.3 Invention steel
    87/121
    Petition 870190036901, of 4/17/2019, p. 90/170
    Steel type Equiaxial grain rate /% TS / MPa El./% λ /% TSxA / MPa-% Sheet thickness / minimum bending radius folding ratio in direction 45 ° - / folding in direction C Note BK1 76 1194 16 33 39402 4.1 1.2 Invention steel BK2 78 1194 16 30 35820 3.5 1.3 Invention steel BL1 72 795 28 116 92220 4.8 1.1 Invention steel BL2 74 785 28 114 89490 3.9 1.2 Invention steel BM1 67 592 29 148 87616 4.2 1.1 Invention steel BO1 63 874 19 100 87400 5.1 1.1 Invention steel BP1 74 1483 11 58 86014 4.1 1.2 Invention steel
    Table 5 - Structures and mechanical characteristics of the respective steels in the respective production conditions (3/4)
    88/121
    Steel type Ratio of random intensity of X-rays of the group of orientations {100} <011> to {223} <110> Random X-ray intensity ratio of {332} <113> rL rC r30 r60 area ratio of coalesced grain /% BQ1 2.8 2.8 0.78 0.80 0.91 0.93 6 BR1 2.8 2.9 0.76 0.79 0.92 0.93 6 BT1 2.8 3.0 0.78 0.80 0.92 0.94 5 BT2 3.4 3.3 0.73 0.76 0.98 0.98 3 BU1 3.0 3.1 0.74 0.77 0.94 0.95 5
    Petition 870190036901, of 4/17/2019, p. 91/170
    Steel type Ratio of random intensity of X-rays of the group of orientations {100} <011> to {223} <110> Intensity ratiorandom X-ray of {332} <113> rL rC r30 r60 area ratio of coalesced grain /% BV1 3.1 3.1 0.76 0.79 0.94 0.95 5 BW1 3.8 3.4 0.78 0.80 1.03 1.03 1 Ba1 2.8 2.9 0.77 0.79 0.96 0.97 6 Bb1 6.5 6.1 0.53 0.64 1.27 1.28 5 Bc1 6.2 6.4 0.42 0.56 1.20 1.22 4 Bd1 6.3 6.4 0.41 0.55 1.19 1.21 3 Be1 3.1 2.8 0.75 0.78 0.91 0.93 5 Bf1 6.4 6J 0.42 0.56 1.18 1.20 3 Bg1 3.0 2.3 0.74 0.77 0.90 0.92 5
    89/121
    Table 5 - Structures and mechanical characteristics of the respective steels in the respective production conditions (4/4)
    Steel type Equiaxial grain rate /% TS / MPa El./% l /% TsxA / MPax% Sheet thickness / minimum bending radius folding ratio in direction 45 ° - / folding in direction C Note BQ1 70 599 32 155 92845 4.8 1.1 Invention steel BR1 72 1110 15 70 77700 4.6 1.1 Invention steel BT1 75 1004 19 74 74296 4.6 1.1 Invention steel BT2 75 989 19 71 70219 3.6 1.2 Invention steel
    Petition 870190036901, of 4/17/2019, p. 92/170
    Steel type Equiaxial grain rate /% TS / MPa El./% l /% TsxA / MPax% Sheet thickness / minimum bending radius folding ratio in direction 45 ° - / folding in direction C Note BU1 74 665 26 140 93100 4.1 1.2 Invention steel BV1 72 755 22 121 91355 4.2 1.2 Invention steel BW1 76 1459 12 51 74409 3.4 1.2 Invention steel Ba1 73 892 14 21 18732 4.5 1.2 Comparative steel Bb1 34 912 12 27 24624 12 2.1 Comparative steel Bc1 38 892 15 61 54412 12 2.4 Comparative steel Bd1 27 1057 8 18 19026 12 2.4 Comparative steel Be1 67 583 26 83 48389 4.5 1.1 Comparative steel Bf1 72 1079 13 14 15106 12 2.3 Comparative steel Bg1 66 688 21 Z2 49536 5.0 1.1 Comparative steel
    90/121
    Petition 870190036901, of 4/17/2019, p. 93/170
    91/121 [EXAMPLE 2] [00232] The technical content of the cold rolled steel sheet according to the configuration will be described using examples of the present invention. [00233] The results of studies will be described in which AC to CW steels having the component compositions shown in Table 6 that satisfied the components specified in the claims of the present invention and comparative Ca to Cg steels were used as examples.
    Petition 870190036901, of 4/17/2019, p. 94/170 [TABLE 6]
    Table 6 - Chemical components (% by mass) - (1/2)
    T1 / ° C Ç Si Mn P s Al N O You Nb HERE 864 0.078 0.82 2.05 0.012 0.004 0.032 0.0026 0.0032 0.02 0.02 CB 852 0.085 0.75 2.25 0.012 0.003 0.035 0.0032 0.0023 - - CC 866 0.110 0.10 1.55 0.020 0.004 0.038 0.0033 0.0026 - 0.04 CD 863 0.350 1.80 2.33 0.012 0.003 0.710 0.0033 0.0021 0.02 - CE 859 0.120 0.22 1.35 0.015 0.003 0.025 0.0055 0.0029 - 0.02 CF 884 0.068 0.50 3.20 0.122 0.002 0.040 0.0032 0.0038 0.03 0.07 CG 858 0.130 0.24 1.54 0.010 0.001 0.038 0.0025 0.0029 - 0.02 CH 899 0.035 0.05 2.20 0.010 0.020 0.021 0.0019 0.0023 0.15 0.03 CK 861 0.144 0.45 2.52 0.007 0.001 0.021 0.0024 0.0031 0.03 - CL 853 0.190 1.40 1.78 0.011 0.002 0.018 0.0032 0.0028 - - CM 866 0.080 0.10 1.40 0.007 0.002 1,700 0.0033 0.0034 - - CO 885 0.120 0.80 2.20 0.008 0.002 0.035 0.0022 0.0035 0.05 - CP 873 0.190 0.55 2.77 0.009 0.002 0.032 0.0033 0.0036 0.04 - QC 852 0.082 0.77 1.82 0.008 0.003 0.025 0.0032 0.0031 - - CR 875 0.030 1.00 2.40 0.005 0.001 0.033 0.0022 0.0011 0.05 0.01 CT 861 0.142 0.70 2.44 0.008 0.002 0.030 0.0032 0.0035 0.03 - ASS 876 0.009 0.10 1.40 0.006 0.001 0.003 0.0033 0.0024 0.10 - CV 853 0.150 0.61 2.20 0.011 0.002 0.028 0.0021 0.0036 - -
    92/121
    Petition 870190036901, of 4/17/2019, p. 95/170
    T1 / ° C Ç Si Mn P s Al N O You Nb CW 1043 0.120 0.17 2.26 0.028 0.009 0.033 0.0027 0.0019 - - Here 860 0.440 0.50 2.20 0.008 0.002 0.035 0.0021 0.0012 - - Cb 854 0.080 0.45 4.50 0.200 0.002 0.034 0.0041 0.0015 - - CC 914 0.080 0.35 2.00 0.008 0.002 0.033 0.0042 0.0034 0.25 - CD 939 0.070 0.35 2.40 0.008 0.002 0.035 0.0035 0.0026 - 0.25 Ce 851 0.090 0.10 1.00 0.008 0.040 0.036 0.0035 0.0022 - - Cf 952 0.070 0.21 2.20 0.008 0.002 0.033 0.0023 0.0036 - - Cg 853 0.140 0.11 1.90 0.008 0.002 0.032 0.0044 0.0035 - -
    Table 6 - Chemical components (% by mass) - (2/2)
    B Mg Landsrare Here Mo Cr W At V Others Note HERE - - - - - - - - - - Invention steel CB - - - - - - - - - Co: 0.5%,Sn: 0.02% Steel of invention CC - - - - - - - - - - Invention steel CD 0.0020 - 0.0035 - - - - - - - Invention steel CE - - - - - - - - - - Invention steel CF - - 0.0044 - - 0.1 - - - - Invention steel CG - - - - - - - - - - Invention steel CH - - 0.0005 0.0009 - - 0.05 - - - Invention steel
    93/121
    Petition 870190036901, of 4/17/2019, p. 96/170
    B Mg Landsrare Here Mo Cr W At V Others Note CK - - - - - - - - - Cu: 0.5%,Ni: 0.25%,Zr: 0.02% invention steel CL 0.0002 - - - - - - - - - Invention steel CM - - - 0.0022 - - - - 0.15 - Invention steel CO - - - - - - - 0.01 0.20 - Invention steel CP - 0.0055 - - 0.022 - - - 0.05 - Invention steel QC 0.0002 - - - - - - - - - Invention steel CR - 0.0040 0.004 - - 0.8 - - - - Invention steel CT 0.0002 - - - - - - - - - Invention steel ASS - - - - 0.010 - - - - - Invention steel CV - 0.0040 0.005 - - - - - - - Invention steel CW - - - - 0.90 - - - - - Invention steel Here - - - - - - - - - - Comparative steel Cb - - - - - - - - - - Comparative steel CC - - - - - - - - - - Comparative steel CD - - - - - - - - - - Comparative steel Ce - - - - - - - - - - Comparative steel
    94/121
    Petition 870190036901, of 4/17/2019, p. 97/170
    B Mg Landsrare Here Mo Cr W At V Others Note Cf - 0.020 - - - - - - 1.10 - Comparative steel Cg - - 0.15 - - - - - - - Comparative steel
    [00234] The steels were cast, reheated in the state or after being cooled to room temperature, heated to the temperature range of 900 ° C to 1300 ° C, then hot rolled under the conditions of Table 7, thus obtaining plates of hot rolled steel with a thickness of 2 mm to 5 mm. The steel sheets were stripped, cold rolled to a thickness of 1.2 mm to 2.3 mm, and annealed under the annealing conditions shown in Table 7. After that, 0.5% sweep lamination was performed, and steel plates were provided to assess the quality of the material.
    [TABLE 7]
    Table 7 - Production conditions (1/2)
    95/121
    Steel type T1 / ° C Number oflamination times of 20% or more at 1000 ° Cat 1200 ° C Lamination reduction rate of 20% or more at 1000 ° Cat 1200 ° C /% Austenite grain diameter / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Temperature increase during lamination at T1 + 30 ° C atT1 + 200 ° C / ° C Total lamination reduction rate at T1 ° C lessof T1 + 30 ° C /% Tf: Temperature after the final pass of the heavy rolling pass / ° C P1: Lamination reduction rate of the final pass of the heavy lamination pass /% CA1 HERE 864 2 45/45 80 85 16 0 984 45 CA2 HERE 864 2 45/45 85 80 15 10 934 45
    Petition 870190036901, of 4/17/2019, p. 98/170
    Steel type T1 / ° C Number oflamination times of 20% or more at 1000 ° Cat 1200 ° C Lamination reduction rate of 20% or more at 1000 ° Cat 1200 ° C /% Austenite grain diameter / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Temperature increaseduring lamination at T1 + 30 ° C atT1 + 200 ° C / ° C Total lamination reduction rate at T1 ° C lessof T1 + 30 ° C /% Tf: Temperature after the final pass of the heavy rolling pass / ° C P1: Lamination reduction rate of the final pass of the heavy lamination pass /% CB1 CB 852 2 45/45 85 80 12 0 982 40 CB2 CB 852 2 45/45 80 85 15 0 922 45 CC1 CC 866 2 45/45 80 85 15 0 966 45 CC2 CC 866 0 - 250 80 16 0 936 45 CD1 CD 863 1 50 120 85 12 0 963 40 CD2 CD 863 2 50 130 35 19 0 963 35 CE1 CE 859 2 45/45 90 95 12 40 909 40 CE2 CE 859 2 45/45 80 80 17 0 929 45 CF1 CF 884 2 45/45 75 85 15 15 944 45 CF2 CF 884 1 50 110 80 11 0 954 40 CG1 CG 858 3 40/40/40 80 80 15 0 958 45 CG2 CG 858 2 40/40/40 80 80 12 10 928 40 CH1 CH 899 2 45/45 80 80 12 20 959 40 CK1 CK 861 3 40/40/40 85 90 12 0 961 40 CK2 CK 853 3 40/40/40 85 90 14 0 923 40 CL1 CL 853 2 45/45 80 85 17 0 953 45 CL2 CL 853 2 45/45 80 80 13 0 923 50
    96/121
    Petition 870190036901, of 4/17/2019, p. 99/170
    Steel type T1 / ° C Number oflamination times of 20% or more at 1000 ° Cat 1200 ° C Lamination reduction rate of 20% or more at 1000 ° Cat 1200 ° C /% Austenite grain diameter / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Temperature increaseduring lamination at T1 + 30 ° C atT1 + 200 ° C / ° C Total lamination reduction rate at T1 ° C lessof T1 + 30 ° C /% Tf: Temperature after the final pass of the heavy rolling pass / ° C P1: Lamination reduction rate of the final pass of the heavy lamination pass /% CM1 CM 866 1 20 150 65 17 10 966 40 CM2 CM 866 1 50 150 60 11 0 966 50 CO1 CO 885 2 45/45 80 60 14 0 985 45 CO2 CO 885 1 50 120 20 15 10 1100 45 CP1 CP 873 2 45/45 75 85 12 0 973 40 CQ1 QC 852 2 45/45 80 80 16 0 952 45 CR1 CR 875 2 45/45 75 85 11 0 985 40 CT1 CT 861 2 45/45 80 95 14 15 961 45 CT2 CT 861 2 45/45 85 80 13 0 931 40 CU1 ASS 876 2 45/45 75 85 13 10 976 40 CV1 CV 853 2 45/45 85 80 12 0 953 40 CW1 CW 1043 1 50 130 80 16 10 1083 45 Ca1 Here 860 2 45/45 75 90 15 0 960 45 Cb1 Cb 854 1 50 120 85 12 0 954 40 CC1 CC 914 2 45/45 75 90 12 0 994 40 Cd1 CD 939 2 45/45 75 85 13 0 999 40 Ce1 Ce 851 2 45/45 80 65 11 0 951 40
    97/121
    Petition 870190036901, of 4/17/2019, p. 100/170
    Steel type T1 / ° C Number oflamination times of 20% or more at 1000 ° Cat 1200 ° C Lamination reduction rate of 20% or more at 1000 ° Cat 1200 ° C /% Austenite grain diameter / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Temperature increaseduring lamination at T1 + 30 ° C atT1 + 200 ° C / ° C Total lamination reduction rate at T1 ° C lessof T1 + 30 ° C /% Tf: Temperature after the final pass of the heavy rolling pass / ° C P1: Lamination reduction rate of the final pass of the heavy lamination pass /% Cf1 Cf 952 2 45/45 80 70 13 0 1012 40 Cg1 Cg 853 2 45/45 75 60 12 0 953 40
    Table 7 - Production conditions (2/2)
    Typeinsteel t1 2.5 x t1 t: waiting time from the end of the heavy rolling pass to the start of cooling / s t / t1 Coil temperature-/ ° C Cold rolling reduction rate /% Annealing temperatureto / ° C Annealing retention time / sec Primary cooling rate / ° C / s Termination temperature ofcoolingprimary / ° C CA1 0.13 0.33 0.28 2.15 500 45 790 60 30 280 CA2 0.66 1.65 1.15 1.75 500 45 660 60 30 280 CB1 0.14 0.34 0.29 2.10 500 45 850 30 30 270 CB2 0.66 1.65 1.15 1.75 500 45 850 90 100 270 CC1 0.22 0.55 0.37 1.68 600 50 800 30 120 350 CC2 0.66 1.65 1.15 1.75 600 50 800 30 120 350 CD1 0.34 0.85 0.49 1.44 600 40 820 40 100 290 CD2 0.51 1.28 0.70 1.37 600 40 820 40 30 290 CE1 1.32 3.30 1.47 1.11 600 50 740 40 120 350
    98/121
    Petition 870190036901, of 4/17/2019, p. 101/170
    Typeinsteel t1 2.5xt1 t: waiting time from the end of the heavy rolling pass to the start of cooling / s t / t1 Coil temperature-/ ° C Cold rolling reduction rate /% Annealing temperature / ° C Annealing retention time / sec Primary cooling rate / ° C / s Termination temperature ofcoolingprimary / ° C CE2 0.66 1.65 1.15 1.75 600 50 740 40 30 350 CF1 0.89 2.22 1.04 1.17 500 40 830 90 100 300 CF2 0.83 2.08 6.00 7.21 500 40 830 90 100 300 CG1 0.22 0.55 0.37 1.68 600 55 760 30 30 330 CG2 0.83 2.08 0.04 0.05 600 40 760 30 100 330 CH1 1.06 2.65 1.21 1.14 500 45 850 90 120 320 CK1 0.34 0.85 0.49 1.44 550 40 855 30 30 270 CK2 0.83 2.08 0.98 1.18 600 45 800 90 30 400 CL1 0.22 0.55 0.37 1.68 600 45 800 30 30 400 CL2 0.51 1.28 0.66 1.29 600 45 800 30 100 400 CM1 0.34 0.85 0.49 1.44 500 50 840 60 100 300 CM2 0.15 0.38 0.25 1.67 500 20 840 60 100 300 CO1 0.22 0.55 0.37 1.68 600 40 800 30 100 270 CO2 0.66 1.65 1.15 1.75 600 40 800 30 100 270 CP1 0.34 0.85 0.49 1.44 600 40 800 40 30 250 CQ1 0.22 0.55 0.37 1.68 600 50 810 40 110 350 CR1 0.24 0.60 0.39 1.63 500 40 830 90 100 350 CT1 0.22 0.55 0.37 1.68 500 50 870 30 100 350
    99/121
    Petition 870190036901, of 4/17/2019, p. 102/170
    Typeinsteel t1 2.5xt1 t: waiting time from the end of the heavy rolling pass to the start of cooling / s t / t1 Coil temperature-/ ° C Cold rolling reduction rate /% Annealing temperature / ° C Annealing retention time / sec Primary cooling rate / ° C / s Termination temperature ofcoolingprimary / ° C CT2 0.83 2.08 0.98 1.18 500 50 870 30 30 350 CU1 0.34 0.85 0.49 1.44 500 45 850 30 120 350 CV1 0.34 0.85 0.49 1.44 600 50 860 40 100 320 CW1 1.46 3.66 1.61 1.10 550 40 800 40 120 350 Ca1 0.22 0.55 0.37 1.68 600 45 820 30 100 350 Cb1 0.34 0.85 0.49 1.44 600 45 820 30 100 350 CC1 0.64 1.59 0.79 1.24 600 45 820 30 100 350 Cd1 1.06 2.65 1.21 1.14 600 45 820 30 100 350 Ce1 0.34 0.85 0.49 1.44 600 50 820 30 100 350 Cf1 1.06 2.65 1.21 1.14 600 40 820 30 100 350 Cg1 0.34 0.85 0.49 1.44 600 55 820 30 100 350
    100/121
    Petition 870190036901, of 4/17/2019, p. 103/170
    101/121 [00235] Table 6 shows the chemical components of the respective steels, and Table 7 shows the respective production conditions. In addition, Table 8 shows the structures and mechanical characteristics of steel sheets. As an index of the local deformation capacity, the hole expansion rate and the bending radius limit through the V-shaped bend were used. In the bending tests, the bending in the C direction and the bending in the 45 ° direction were used. performed, and the rates were used as an index of dependence on the orientation of conformation capacity. The tensile tests and the bending tests were based on the JIS Z2241 and the 90 ° V block bending tests were based on the Japan Iron and Steel Federation standard JFS T1001, respectively. The ratio of random X-ray intensity was measured using the EBSD at an extreme intensity of 0.5 pm in relation to the location at 1 Λ from the end portion in the width direction in a central portion of the plate thickness in an area 5/8 to 3/8 of a cross section parallel to the rolling direction. In addition, the r values in the respective directions were measured using the methods above
    Petition 870190036901, of 4/17/2019, p. 104/170 [TABLE 8]
    Table 8 - The structures and mechanical characteristics of the respective steels in the respective production conditions (1/4)
    Steel type Ratio of random intensity of X-rays of the group of orientations {100} <011> to {223} <110> Random X-ray intensity ratio of {332} <113> rL rC r30 r60 Area ratio of coalesced grain /% CA1 HERE 2.6 2.5 0.83 0.84 0.85 0.88 9 CA2 HERE 4.4 3.0 0.80 0.81 0.90 0.92 15 CB1 CB 2.1 2.6 0.84 0.85 0.86 0.89 8 CB2 CB 2.5 3.0 0.79 0.81 0.90 0.92 6 CC1 CC 3.0 2.5 0.78 0.80 0.91 0.93 5 CC2 CC 5.0 3.5 0.40 0.40 1.26 1.15 15 CD1 CD 3.1 3.8 0.83 0.84 0.99 0.99 5 CD2 CD 5.1 52 0.84 0.85 0.95 0.96 12 CE1 CE 52 7.1 0.73 0.75 1.01 1.01 8 CE2 CE 3.6 2.5 0.79 0.81 0.90 0.92 5 CF1 CF 3.2 4.0 0.72 0.75 0.97 0.98 3 CF2 CF 1.1 1.2 0.95 0.95 0.99 1.01 30 CG1 CG 3.4 2.0 0.78 0.80 0.91 0.93 4 CG2 CG 5.1 52 0.61 0.66 1.40 1.38 30 CH1 CH 3.1 3.6 0.72 0.76 0.97 0.98 1
    102/121
    Petition 870190036901, of 4/17/2019, p. 105/170
    Steel type Ratio of random intensity of X-rays of the group of orientations {100} <011> to {223} <110> Random X-ray intensity ratio of {332} <113> rL rC r30 r60 Area ratio of coalesced grain /% CK1 CK 2.7 3.8 0.76 0.79 0.95 0.96 5 CK2 CK 3.5 3.5 0.73 0.76 0.99 0.99 2 CL1 CL 3.0 3.0 0.78 0.80 0.91 0.93 6 CL2 CL 3.4 3.4 0.74 0.77 0.95 0.96 3
    Table 8 - The structures and mechanical characteristics of the respective steels in the respective production conditions (2/4)
    Steel type Equiaxial grain rate /% TS / MPa El./% λ /% sheet thickness / minimum bending radius (C fold) Folding ratio in 45 ° direction / folding in C direction Note CA1 67 785 24 121 5.8 1.0 Invention steel CA2 29 805 15 61 06 10 Comparative steel CB1 66 788 24 130 6.5 1.0 Invention steel CB2 71 778 24 125 5.1 1.1 Invention steel CC1 72 598 28 154 4.9 1.1 Invention steel CC2 39 598 22 81 12 2.9 Comparative steel CD1 74 1216 14 29 3.9 1.1 Invention steel CD2 58 1211 8 10 04 12 Comparative steel CE1 81 585 29 82 08 12 Comparative steel
    103/121
    Petition 870190036901, of 4/17/2019, p. 106/170
    Steel type Equiaxial grain rate /% TS / MPa El./% λ /% sheet thickness / minimum bending radius (C fold) Folding ratio in 45 ° direction / folding in C direction Note CE2 69 588 29 151 4.6 1.1 Invention steel CF1 77 1198 14 66 3.3 1.3 Invention steel CF2 30 1100 5 50 6.0 1.0 Invention steel CG1 70 594 29 150 5.0 1.1 Invention steel CG2 30 544 26 Zí 14 2Λ Comparative steel CH1 75 844 20 104 3.6 1.3 Invention steel CK1 76 1194 16 38 3.9 1.2 Invention steel CK2 78 1194 16 30 3.4 1.3 Invention steel CL1 72 795 28 114 4.5 1.1 Invention steel CL2 74 785 28 112 3.6 1.2 Invention steel
    104/121
    Table 8 - The structures and mechanical characteristics of the respective steels in the respective production conditions (3/4)
    Type d and steel Ratio of random intensity of X-rays of the group of orientations {100} <011> to {223} <110> Random X-ray intensity ratio of {332} <113> rL RR r30 r60 Area ratio of coalesced grain /% CM1 CM 2.9 2.8 0.89 0.89 1.00 1.00 3 CM2 CM 2.6 5.5 0.93 0.92 0.96 0.97 15 CO1 CO 3.0 3.5 0.78 0.80 0.89 0.91 7
    Petition 870190036901, of 4/17/2019, p. 107/170
    Type c le steel Ce ratio random intensiCe Ce X-rays Co group Ce orientations {100} <011> to {223} <110> Random Ce intensiCaC ratio Ce X-rays Ce {332} <113> rL RR r30 r60 Ce ratio Co coalesciCo grain /% CO2 CO 5.0 5.5 0.58 0.58 1.18 1.31 17 CP1 CP 3.3 3.8 0.74 0.77 0.94 0.95 5 CQ1 QC 2.9 2.5 0.78 0.80 0.91 0.93 5 CR1 CR 2.8 3.6 0.76 0.79 0.92 0.93 6 CT1 CT 2.3 2.5 0.78 0.80 0.92 0.94 4 CT2 CT 2.8 3.0 0.73 0.76 0.98 0.98 1 CU1 ASS 2.8 3.3 0.74 0.77 0.94 0.95 4 CV1 CV 2.7 2.8 0.76 0.79 0.94 0.95 3 CW1 CW 3.6 4.1 0.79 0.81 1.05 1.04 2 Ca1 Here 2.8 3.0 0.77 0.79 0.96 0.97 6 Cb1 Cb 81 9.3 0.53 0.64 1.27 1.28 4 CC1 CC 83 9.5 0.42 0.56 1.20 1.22 3 Cd1 CD 84 9.6 0.41 0.55 1.19 1.21 2 Ce1 Ce 3.1 2.8 0.75 0.78 0.91 0.93 3 Cf1 Cf 64 81 0.42 0.56 1.18 1.20 3 Cg1 Cg 3.1 2.3 0.74 0.77 0.90 0.92 2
    105/121
    Petition 870190036901, of 4/17/2019, p. 108/170
    Table 8 - The structures and mechanical characteristics of the respective steels in the respective production conditions (4/4)
    Steel type Equiaxial grain rate /% TS / MPThe El./% l /% sheet thickness / minimum bending radius (C fold) Folding ratio in 45 ° direction / folding in C direction Note CM1 67 592 29 157 5.0 1.1 Invention steel CM2 30 592 25 99 0.5 1.5 Comparative steel CO1 63 874 19 98 4.2 1.1 Invention steel CO2 29 884 14 23 14 00 Invention steel CP1 74 1483 11 56 3.6 1.2 Invention steel CQ1 70 600 32 154 5.0 1.1 Invention steel CR1 72 1110 15 71 4.2 1.1 Invention steel CT1 75 1004 19 82 5.5 1.1 Invention steel CT2 75 989 19 78 4.1 1.2 Invention steel CU1 74 665 26 143 4.2 1.2 Invention steel CV1 72 756 22 126 4.8 1.2 Invention steel CW1 76 1459 12 53 3.1 1.2 Invention steel Ca1 73 893 14 21 4.4 1.2 Comparative steel Cb1 34 912 12 28 08 2.1 Comparative steel CC1 38 893 15 61 07 2.4 Comparative steel Cd1 27 1058 8 18 07 2.4 Comparative steel
    106/121
    Petition 870190036901, of 4/17/2019, p. 109/170
    Steel type Equiaxial grain rate /% TS / MPThe El./% l /% sheet thickness / minimum bending radius (C fold) Folding ratio in 45 ° direction / folding in C direction Note Ce1 67 583 26 83 4.5 1.1 Comparative steel Cf1 72 1079 13 14 09 2.3 Comparative steel Cg1 66 688 21 72 5.0 1.1 Comparative steel
    107/121
    Petition 870190036901, of 4/17/2019, p. 110/170
    108/121 [EXAMPLE 3] [00236] The technical content of the galvanized steel sheet according to the configuration will be described using examples of the present invention. [00237] The results of studies will be described in which steels from DA to DL were used, having the components shown in Table 9.
    Petition 870190036901, of 4/17/2019, p. 111/170 [TABLE 9]
    Table 9 - Chemical components (% by mass)
    Part 1
    T1 / ° C Ç Si Mn P s Al N O You GIVES 857 0.114 0.05 2.15 0.012 0.004 0.590 0.0026 0.0032 - DB 868 0.087 0.62 2.03 0.012 0.003 0.180 0.0032 0.0023 0.022 A.D 852 0.140 0.87 1.20 0.009 0.004 0.038 0.0033 0.0026 - DD 858 0.145 0.10 2.33 0.012 0.003 0.710 0.0033 0.0021 0.017 IN 873 0.220 0.13 2.96 0.015 0.003 0.120 0.0029 0.0029 0.024 DF 882 0.068 0.50 2.31 0.009 0.002 0.040 0.0032 0.0038 0.03 DG 851 0.061 0.11 2.20 0.010 0.001 0.038 0.0025 0.0029 - DH 900 0.035 0.05 1.80 0.010 0.001 0.021 0.0019 0.0023 0.17 DI 861 0.410 0.08 2.60 0.190 0.002 0.041 0.0029 0.003 - DJ 1220 0.051 0.07 1.67 0.008 0.002 0.029 0.0034 0.0031 0.65 DK 853 0.150 0.61 2.20 0.011 0.002 0.028 0.0021 0.0036 - DL 1045 0.120 0.17 2.26 0.028 0.090 0.033 0.0027 0.0019 -
    109/121
    Petition 870190036901, of 4/17/2019, p. 112/170
    Part 2
    Nb B Mg Landsrare Here Mo Cr V W At Others GIVES - 0.0005 - - - 0.04 - - - - - DB 0.017 0.0012 - - - - 0.44 - - - - A.D - - - - - - - - - - - DD - 0.0005 - 0.0014 - - - - - - - IN 0.021 - 0.0035 - 0.0015 - - 0.029 - - - DF 0.065 - - 0.0021 - - - - - - - DG - - - - - - - - 0.05 0.01 Cu: 0.5%,Ni: 0.25%,Co: 0.5,Sn: 0.02%,Zr: 0.02% DH 0.02 0.0014 - 0.0005 0.0009 - - - - - DI - - - - - - - - - - - DJ 0.59 - - - - - - - - - - DK - - 0.090 0.10 - - - - - - - DL - 0.0520 - - - 19 - - - - -
    110/121
    Petition 870190036901, of 4/17/2019, p. 113/170 [00238] The steels were cast, reheated in the state or after being cooled to room temperature, heated to a temperature range of 900 ° C to 1300 ° C, then cold rolled under the conditions of Table 10, obtaining thus hot-rolled steel sheets with a thickness of 2 mm to 5 mm. The steel sheets were pickled, cold rolled to a thickness of 1.2 mm to 2.3 mm, annealed under the annealing conditions shown in Table 10, and continuously subjected to galvanized annealing and coating or galvanized coating treatment. and annealed using a galvanized coating bath. After that, a sweep lamination at 0.5% was performed and the steel sheets were provided to assess the quality of the material.
    Petition 870190036901, of 4/17/2019, p. 114/170 [TABLE 10]
    Table 10 - Production conditions (1/2)
    Kind of T1 / ° C Number oflamination times of 20% or less at 1000 ° Cat 1200 ° C Lamination reduction rate of 20% or moreat 1000 ° C at1200 ° C /% Diameter of austenite grain / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Temperature increase during lamination at T1 + 30 ° C atT1 + 200 ° C / ° C Lamination reduction ratetotal at T1 ° Cless thanT1 + 30 ° C /% Tf: Temperature after final pass of heavy rolling pass / ° C P1: Reduction rate of final pass of heavy pass /% The ço 30 GIVES 857 1 50 130 90 15 0 955 45 31 GIVES 857 2 45/45 85 85 10 0 975 40 32 DB 868 2 45/45 85 80 10 10 950 35 33 DB 868 2 45/45 90 85 10 5 925 35 34 A.D 852 2 45/45 90 85 15 15 960 30 35 A.D 852 2 45/45 95 95 17 0 935 35 36 DD 858 3 40/40/40 70 85 15 25 980 30 37 IN 873 2 45/45 85 80 17 5 955 30 38 IN 873 1 50 110 80 18 15 925 30 39 DF 882 3 40/40/40 75 90 18 0 965 35 40 DG 851 3 40/40/40 95 85 10 0 945 35 41 DH 900 2 45/45 75 90 13 0 990 40 42 DH 900 2 45/45 80 85 15 10 985 40 43 DF 882 1 50 100 65 20 25 935 45 44 DG 851 1 50 150 70 20 15 905 45
    112/121
    Petition 870190036901, of 4/17/2019, p. 115/170
    Steel type T1 / ° C Number oflamination times of 20% or less at 1000 ° Cat 1200 ° C Lamination reduction rate of 20% or moreat 1000 ° C at1200 ° C /% Diameter of austenite grain / pm Total lamination reduction rate at T1 + 30 ° C atT1 + 200 ° C /% Increase oftemperature during lamination at T1 + 30 ° C atT1 + 200 ° C / ° C Lamination reduction ratetotal at T1 ° Cless thanT1 + 30 ° C /% Tf: Temperature after final pass of heavy rolling pass / ° C P1: Reduction rate of final pass of heavy pass /% 45 DG 851 1 20 150 60 21 20 890 45 46 DH 900 1 50 120 65 19 10 950 45 47 DH 900 1 50 120 35 12 45 880 30 48 GIVES 857 2 45/45 90 45 20 45 900 30 49 DB 868 2 45/45 90 45 15 45 1050 30 50 A.D 852 2 40/45 85 70 15 45 890 30 51 DG 851 0 - 370 45 30 35 885 45 52 IN 873 1 50 120 80 40 35 860 40 53 GIVES 857 0 - 240 60 18 20 855 30 54 A.D 852 0 - 220 85 14 25 880 45 55 GIVES 852 2 45/45 85 85 10 0 975 40 56 DB 852 2 45/45 90 85 10 5 925 35 57 A.D 852 2 45/45 90 85 25 15 910 45 58 DG 851 3 40/40/40 95 85 22 0 905 40 59 DI 861 Cracked during casting or hot rolling 60 DJ 1220 Cracked during casting or hot rolling 61 DK 853 Cracked during casting or hot rolling 62 DL 1045 Cracked during casting or hot rolling
    113/121
    Petition 870190036901, of 4/17/2019, p. 116/170
    Table 10 - Production conditions (2/2)
    Typeinsteel t1 2.5 x t1 t: Waiting time from the end of the heavy rolling pass to the start of cooling / s t / t1 Coil temperature-/ ° C Cold rolling reduction rate /% Annealing temperature / ° C Annealing retention time / sec Rate ofcoolingcousin-river / ° C / s Primary cooling end temperature / ° C 30 0.23 0.58 0.30 1.28 580 60 820 60 3 650 31 0.18 0.45 0.20 1.11 520 60 820 60 3 650 32 0.79 1.98 1.10 1.39 550 50 840 30 5 680 33 1.32 3.29 1.90 1.44 600 50 840 30 5 680 34 0.61 1.54 0.90 1.46 550 50 830 40 3 640 35 0.77 1.93 1.00 1.29 570 50 830 40 3 640 36 0.45 1.12 0.60 1.34 530 45 850 90 2 700 37 1.02 2.55 1.50 1.47 600 40 825 90 2 680 38 1.64 4.10 2.40 1.46 600 40 825 90 2 680 39 0.78 1.94 1.00 1.29 620 60 850 30 5 650 40 0.60 1.51 0.90 1.49 600 60 860 30 5 650 41 0.48 1.19 0.70 1.47 450 50 680 30 5 620 42 0.55 1.38 0.70 1.26 450 50 680 30 5 620 43 1.07 2.67 2.00 1.88 620 60 850 30 5 650 44 1.05 2.63 1.50 1.43 600 60 860 30 5 650 45 1.51 3.77 2.60 1.72 600 60 860 30 5 650 46 1.16 2.90 1.50 1.29 600 60 860 30 5 650 47 3.80 9.49 4.00 1.05 600 60 860 30 5 650
    114/121
    Petition 870190036901, of 4/17/2019, p. 117/170
    Typeinsteel t1 2.5xt1 t: Waiting time from the end of the heavy rolling pass to the start of cooling / s t / t1 Coil temperature-/ ° C Cold rolling reduction rate /% Annealing temperature / ° C Annealing retention time / sec Rate ofcoolingcousin-river / ° C / s Primary cooling end temperature / ° C 48 1.85 4.62 4.80 2.60 580 60 820 60 3 650 49 0.13 0.32 0.10 0.77 550 50 840 30 5 680 50 1.98 4.95 1.00 0.51 550 50 840 30 5 680 51 1.68 4.20 0.40 0.24 600 40 825 90 2 680 52 3.69 9.22 9.00 2.44 530 45 850 90 2 700 53 3.15 7.88 0.80 0.25 580 60 820 60 3 650 54 1.87 4.69 2.00 1.07 570 50 830 40 3 640 55 0.16 0.39 0.20 1.28 720 60 780 60 0.05 725 56 0.96 2.41 2.00 2.08 600 50 950 05 5 600 57 0.93 2.32 1.00 1.08 750 10 830 40 3 640 58 1.22 3.06 1.30 1.06 600 60 600 30 5 650 59 Cracked during casting or hot rolling 60 Cracked during casting or hot rolling 61 Cracked during casting or hot rolling 62 Cracked during casting or hot rolling
    115/121
    Petition 870190036901, of 4/17/2019, p. 118/170
    116/121 [00239] Table 9 shows the chemical components of the respective steels, Table 10 shows the respective production conditions, and Table 11 shows the structures and mechanical characteristics of the steel sheets under the respective production conditions.
    [00240] As an index of the local deformation capacity, the hole expansion rate and the bending radius limit through the V-shaped bend at 90 ° were used. The tensile tests and the folding tests were based on the JIS Z2241 and the 90 ° folding tests of V blocks of the JIS Z 2248, and the hole expansion tests were based on the Japan Iron and Steel Federation standard JFS T1001 , respectively. The random X-ray intensity ratio was measured using EBSD at an extreme intensity of 0.5 pm relative to the location 1/4 from the end portion in the width direction in a central portion of the plate thickness in an area 3/8 to 5/8 of a cross section parallel to the rolling direction. In addition, the r values in the respective directions were measured using the methods above.
    Petition 870190036901, of 4/17/2019, p. 119/170 [TABLE 11]
    Table 11 - The structure and mechanical characteristics of the respective steels and the respective production conditions (1/2)
    Type c le steel Ce ratio random intensiCe Ce X-rays Co group Ce orientations {100} <011> to {223} <110> Random Ce intensiCaC ratio Ce X-rays Ce {332} <113> rL rC r30 r60 30 GIVES 2.5 2.2 0.81 0.86 0.97 0.98 31 GIVES 2.4 2.3 0.85 0.82 0.92 0.91 32 DB 2.1 2.3 0.90 0.93 0.92 0.98 33 DB 2.3 2.5 0.88 0.91 0.98 1.00 34 A.D 2.5 2.3 0.78 0.75 0.85 0.82 35 A.D 2.6 2.8 0.85 0.89 0.98 1.00 36 DD 3.0 3.1 0.70 0.70 1.08 1.08 37 IN 2.9 3.0 0.76 0.80 1.06 1.05 38 IN 3.3 3.0 0.72 1.00 0.97 1.09 39 DF 2.3 2.4 0.85 0.88 1.03 1.05 40 DG 2.4 2.3 0.82 0.90 1.00 0.98 41 DH 2.7 2.8 0.73 0.75 0.98 1.00 42 DH 2.9 3.0 0.75 0.78 0.95 1.10 43 DF 3.9 4.8 0.63 0.76 1.05 1.20 44 DG 3.4 3.7 0.62 0.77 1.08 1.19 45 DG 3.9 4.8 0.60 0.75 1.10 1.28
    117/121
    Petition 870190036901, of 4/17/2019, p. 120/170
    Steel type Ratio of random intensity of X-rays of the group of orientations {100} <011> to {223} <110> Random X-ray intensity ratio of {332} <113> rL rC r30 r60 46 DH 3.9 4.9 0.62 0.80 1.04 1.17 47 DH 6.7 6.7 0.51 0.61 1.25 1.30 48 GIVES 41 5.3 0.63 0.68 1.12 1.20 49 DB 5.8 5.2 0.55 0.69 1.18 1.26 50 A.D 6.8 5.9 0.60 0.65 1.13 1.15 51 DG 7.2 51 0.50 0.69 1.20 1.29 52 IN 6.8 6.0 0.50 0.65 1.16 1.20 53 GIVES 3.9 5.2 0.59 0.75 1.06 1.24 54 A.D 3.8 5.1 0.68 0.72 1.18 1.10 55 GIVES 42 5.1 0.67 0.65 1.15 1.16 56 DB 5.8 5.2 0.69 0.60 1.11 1.13 57 A.D 49 5.8 0.54 0.65 0.90 1.11 58 DG 6.5 6.1 0.52 0.60 0.89 1.13 59 DI Cracked during casting or hot rolling 60 DJ Cracked during casting or hot rolling 61 DK Cracked during casting or hot rolling 62 DL Cracked during casting or hot rolling
    118/121
    Petition 870190036901, of 4/17/2019, p. 121/170
    Table 11 - The structure and mechanical characteristics of the respective steels and the respective production conditions (1/2)
    Steel type TS / MPa El./% λ /% TSxÀ / MPa-% sheet thickness / minimum bending radius Note 30 1000 16 55 55000 3.6 Invention steel 31 1010 17 60 60600 4.0 Invention steel 32 1050 16 65 68250 5.3 Invention steel 33 1065 15 70 74550 5.3 Invention steel 34 1230 13 60 73800 3.6 Invention steel 35 1250 12 55 68750 4.5 Invention steel 36 1275 10 50 63750 3.2 Invention steel 37 1485 9 50 74250 2.6 Invention steel 38 1475 8 55 81125 2.3 Invention steel 39 805 24 75 60375 2.8 Invention steel 40 635 32 60 38100 4.7 Invention steel 41 785 22 145 113825 3.6 Invention steel 42 800 21 140 112000 3.0 Invention steel 43 840 19 60 50400 1.8 Invention steel 44 640 30 50 32000 1.8 Invention steel 45 630 31 45 28350 1.6 Invention steel 46 825 17 100 82500 1.6 Invention steel
    119/121
    Petition 870190036901, of 4/17/2019, p. 122/170
    Steel type TS / MPa El./% λ /% TSxÀ / MPa-% sheet thickness / minimum bending radius Note 47 805 19 80 64400 0.9 Comparative steel 48 980 18 30 29400 0.9 Comparative steel 49 1100 12 45 49500 0.8 Comparative steel 50 990 16 35 34650 0.9 Comparative steel 51 650 29 40 26000 0.9 Comparative steel 52 1490 8 30 44700 07 Comparative steel 53 985 16 35 34475 u. Comparative steel 54 1265 9 45 56925 u. Comparative steel 55 890 17 30 26700 0.8 Comparative steel 56 1150 10 35 40250 0.8 Comparative steel 57 1240 12 35 43400 0.9 Comparative steel 58 560 30 40 22400 0.9 Comparative steel 59 Cracked during casting or hot rolling Comparative steel 60 Cracked during casting or hot rolling Comparative steel 61 Cracked during casting or hot rolling Comparative steel 62 Cracked during casting or hot rolling Comparative steel
    120/121
    Petition 870190036901, of 4/17/2019, p. 123/170
    121/121 [00241] As shown, for example, in FIGS. 40, 41, 42, 43.44 and 45, steel sheets that meet the specifications of the present invention had excellent bore expansion properties, bending properties, and small anisotropy in forming. In addition, steel sheets produced in the range of desirable conditions had a higher bore expansion rate and bending properties.
    INDUSTRIAL APPLICABILITY [00242] As described above, according to the present invention, without limiting the configuration of the main structure, it is possible to obtain a hot-rolled steel plate, a cold-rolled steel plate, and a galvanized steel plate that they are excellent in terms of local deformation capacity and have a small influence of orientation of conformation capacity even when Nb, Ti, and the like are added to control the texture in addition to the control of the sizes and shapes of the crystal grains;
    [00243] Therefore, the present invention is highly useful in the steel industry.
    [00244] In addition, in the present invention, the strength of the steel sheet is not specified; however, since the forming capacity degrades as the strength increases, the effects are particularly great in the case of a high-strength steel plate, for example, a case in which the tensile strength is 440 MPa or more.
    权利要求:
    Claims (25)
    [1]
    1. Hot-rolled steel sheet, characterized by the fact that it consists of, in% by mass:
    C: 0.0001% to 0.40%;
    Si: 0.001% to 2.5%;
    Mn: 0.001% to 4.0%;
    P: 0.001% to 0.15%;
    S: 0.0005% to 0.03%;
    Al: 0.001% to 2.0%;
    N: 0.0005% to 0.01%;
    O: 0.0005% to 0.01%; and one or two or more elements between Ti: 0.001% to 0.20%;
    Nb: 0.001% to 0.20%;
    V: 0.001% to 1.0%;
    W: 0.001% to 1.0%;
    B: 0.0001% to 0.0050%;
    Mo: 0.001% to 1.0%;
    Cr: 0.001% to 2.0%;
    Cu: 0.001% to 2.0%;
    Ni: 0.001% to 2.0%;
    Co: 0.0001% to 1.0%;
    Sn: 0.0001% to 0.2%;
    Zr: 0.0001% to 0.2%;
    As: 0.0001% to 0.50%;
    Mg: 0.0001% to 0.010%;
    Ca: 0.0001% to 0.010%; and rare earths: 0.0001% to 0.1%;
    and the composite iron balance and the inevitable impurities, in which the average value of the random intensity ratio of
    Petition 870180044077, of 05/24/2018, p. 126/181
    [2]
    2/9 X-rays of a group of orientations {100} <011> to {223} <110> at least in a central portion of the plate thickness, that is, in a plate thickness range from 5/8 to 3 / 8 from the plate surface is 1.0 to 6.0, the random X-ray intensity ratio of a {332} <113> crystal orientation is 1.0 to 5.0; and rC which is a value r in a direction perpendicular to the lamination direction is 0.70 to 1.10 and r30 which is a value r in a direction that forms an angle of 30 ° to the lamination direction is 0, 70 to
    1.10.
    2. Hot-rolled steel sheet according to Claim 1, characterized by the fact that rL, which is a value r in the rolling direction, is 0.70 to 1.10 and r60, which is a value r in the direction which forms an angle of 60 ° in relation to the rolling direction, is 0.70 to 1.10.
    [3]
    Hot-rolled steel sheet according to Claim 1 or 2, characterized by the fact that one or two or more between bainite, martensite, perlite and austenite are present in the hot-rolled steel sheet, and the grain ratio having a dL / dt, which is the ratio of the length in the lamination direction dL to the length in the direction of the thickness of the dt plate, from 3.0 or less in crystal grains in the structures is 50% to 100%.
    [4]
    4. Hot-rolled steel sheet according to Claim 1 or 2, characterized by the fact that the area ratio of the crystal grains having a grain diameter of more than 20 pm in a total area of metal structure in the sheet hot rolled steel is 0% to 10%.
    [5]
    5. Cold-rolled steel sheet obtained by cold-rolling the hot-rolled steel sheet as defined in Claim 1, characterized by the fact that the average value of the InPetition ratio 870180044077, of 05/24/2018, p. 127/181
    3/9 random X-ray tension of the orientation group {100} <011> to {223} <110> at least in the central portion of the plate thickness is
    1.0 to less than 4.0, the ratio of the random X-ray intensity of the {332} <113> crystal orientation is 1.0 to 5.0; and rC which is the value r in a direction perpendicular to the lamination direction is 0.70 to 1.10, and r30 which is the value r in a direction that forms an angle of 30 ° to the lamination direction is 0 , 70 to
    1.10.
    [6]
    6. Cold rolled steel sheet according to Claim 5, characterized by the fact that rL which is the r value in the rolling direction is 0.70 to 1.10, and r60 which is the r value in a forming direction. an angle of 60 ° to the lamination direction is 0.70 to 1.10.
    [7]
    7. Cold rolled steel sheet according to Claim 5 or 6, characterized by the fact that one or two or more between bainite, martensite, perlite and austenite are present in the cold rolled steel sheet and a proportion of the grains having a dL / dt ratio, which is the ratio of the length in the lamination direction dL to the length in the direction of the thickness of the plate dt, from 3.0 or less in crystal grains in the structure is 50% to 100%.
    [8]
    8. Cold rolled steel sheet according to Claim 5 or 6, characterized by the fact that the area ratio of the crystal grains having a grain diameter of more than 20 mm in a total area of a metal structure in the plate cold rolled steel is 0% to 10%.
    [9]
    9. Galvanized steel sheet, characterized by the fact that it also comprises a layer of galvanized coating or a layer of galvanized and annealed coating on a surface of the cold rolled steel sheet as defined in Claim 5, wherein the average ratio value random intensity of
    Petition 870180044077, of 05/24/2018, p. 128/181
    4/9 X-rays of the guidance group {100} <011> to {223} <110> at least in the central portion of the plate thickness is 1.0 to less than 4.0, the random X-ray intensity ratio crystal orientation {332} <113> is 1.0 to 5.0; and rC which is the r value in a direction perpendicular to the rolling direction is 0.70 to 1.10, and r30 which is the r value in a direction forming an angle of 30 ° with the rolling direction is 0.70 to 1.10.
    [10]
    10. Galvanized steel sheet according to Claim 9, characterized by the fact that rL, which is the value r in the rolling direction is 0.70 to 1.10, and r60 which is the value r in a direction forming an angle of 60 ° in relation to the rolling direction is 0.70 to
    1.10.
    [11]
    11. Hot-rolled steel plate production method, the method characterized by the fact that it initially comprises hot rolling carried out at least once at a rate of reduction of 20% or more in a temperature range of 1000 ° C at 1200 ° C, and the austenite grain diameter is adjusted to 200 mm or less, where an ingot or plate consisting of, by weight%:
    C: 0.0001% to 0.40%,
    Si: 0.001% to 2.5%,
    Mn: 0.001% to 4.0%,
    P: 0.001% to 0.15%,
    S: 0.0005% to 0.03%,
    Al: 0.001% to 2.0%,
    N: 0.0005% to 0.01%,
    O: 0.0005% to 0.01%, and one or two or more elements between:
    Ti: 0.001% to 0.20%,
    Nb: 0.001% to 0.20%,
    Petition 870180044077, of 05/24/2018, p. 129/181
    5/9
    V: 0.001% to 1.0%,
    W: 0.001% to 1.0%,
    B: 0.0001% to 0.0050%,
    Mo: 0.001% to 1.0%,
    Cr: 0.001% to 2.0%,
    Cu: 0.001% to 2.0%,
    Ni: 0.001% to 2.0%,
    Co: 0.0001% to 1.0%,
    Sn: 0.0001% to 0.2%,
    Zr: 0.0001% to 0.2%,
    As: 0.0001% to 0.50%,
    Mg: 0.0001% to 0.010%,
    Ca: 0.0001% to 0.010%, and rare earths: 0.0001% to 0.1% and the balance composed of iron and the inevitable impurities; secondly, a hot lamination in which the total reduction ratio is 50% or more is carried out in a temperature range from T1 + 30 ° C to T 1 + 200 ° C;
    thirdly, a hot lamination in which the total lamination reduction is less than 30% is carried out in a temperature range from T1 ° C to less than T 1 + 30 ° C; and the hot rolling ends at a transformation temperature Ar3 or higher, where T1 is the temperature determined by the steel plate components, and expressed by the following formula 1:
    T1 (° C) = 850 + 10 x (C + N) x Mn + 350 x Nb + 250 x Ti + 40 x B + 10 x Cr + 100 x Mo + 100 x V ··· (Formula 1)
    [12]
    12. Hot-rolled steel plate production method according to Claim 11, characterized by the fact that, in the second rolling process, the
    Petition 870180044077, of 05/24/2018, p. 130/181
    6/9 hot in the Ti + 30 ° C to Ti + 200 ° C temperature range, the ingot or plate is laminated at least once at a lamination reduction rate of 30% or more in one pass.
    [13]
    13. Hot-rolled steel plate production method according to Claim 11 or 12, characterized in that in the first hot rolling in a temperature range of 1000 ° C to 1200 ° C, the ingot or plate is laminated at least twice at a lamination reduction ratio of 20% or more, and the austenite grain diameter is adjusted to 100 pm or less.
    [14]
    14. Hot-rolled steel plate production method according to Claim 11 or 12, characterized by the fact that, in a case where the rolling reduction ratio is 30% or more in the temperature range of T1 + 30 ° C to T1 + 200 ° C is defined as a large reduction in the pass, for the start of cooling it uses a configuration that satisfies the following formula 2, t1 <t <t1 x 2.5 ··· (Formula 2) in that t1 is expressed by the formula 3 below;
    t1 = 0.001 x ((Tf - T1) x P1) 2 - 0.109 x ((Tf - T1) x P1) + 3.1 ··· (Formula 3) where Tf represents the temperature after the final pass, and
    P1 represents the lamination reduction ratio in the final pass.
    [15]
    15. Method of production of the hot-rolled steel sheet according to Claim 14, characterized by the fact that the temperature of the steel sheet increases by 18 ° C or less between the respective passes of the second hot-rolling in the temperature range from T1 + 30 ° C to T1 + 200 ° C.
    [16]
    16. Production method of cold rolled steel plate, the method characterized by the fact that it comprises, stripping, after the end of the hot rolling process, the hot rolled steel plate obtained through the production method of plate 870180044077, of 05/24/2018, p. 131/181
    7/9 pa of hot-rolled steel as defined in Claim 11 at the temperature of the transformation point Ar3 or more;
    cold rolling at 20% to 90%;
    annealing at a temperature range of 720 ° C to 900 ° C for a retention time of 1 second at 300 seconds;
    accelerated cooling with a cooling rate of 10 ° C / s to 200 ° C / s from 650 ° C to 500 ° C; and retention at a temperature of 200 ° C to 500 ° C.
    [17]
    17. Cold rolled steel sheet production method according to Claim 16, characterized by the fact that, in the second hot rolling in the temperature range from T1 + 30 ° C to T1 + 200 ° C, a lamination reduction ratio of 30% or more in one pass is performed at least once.
    [18]
    18. Method of producing cold-rolled steel sheet according to Claim 16 or 17, characterized by the fact that, in the first hot rolling in the temperature range of 1000 ° C to 1200 ° C, rolling at a ratio reduction of 20% or more is performed at least twice, and the austenite grain diameter is adjusted to 100 pm or less.
    [19]
    19. Method of producing a cold rolled steel sheet according to Claim 16 or 17, characterized by the fact that, in a case where the pass in which the rolling reduction ratio is 30% or more in the range of temperatures from T1 + 30 ° C to T1 + 200 ° C is defined as a big reduction in the pass, the waiting time t from the end of a final pass of the big reduction pass to the beginning of the cooling employs a configuration that satisfies equation 4 below, t1 <t <t1 x 2.5 ··· (Formula 4) where t1 is expressed by formula 5 below;
    t1 = 0.001 x ((Tf - T1) x P1) 2 - 0.109 x ((Tf - T1) x P1) + 3.1
    Petition 870180044077, of 05/24/2018, p. 132/181
    8/9 ··· (Formula 5) where Tf represents the temperature after the final pass and Pi represents the lamination reduction ratio in the final pass.
    [20]
    20. Method of producing cold-rolled steel sheet according to Claim 19, characterized by the fact that the temperature of the steel sheet increases by 18 ° C or less between the respective passes of the second hot rolling in the temperature range from Ti + 30 ° C to Ti + 200 ° C.
    [21]
    21. Method of producing a galvanized steel sheet, the method characterized by the fact that it comprises, winding in a temperature range of 680 ° C to room temperature, after the end of the hot rolling of the steel sheet hot obtained by the hot rolled steel sheet production method as defined in Claim 11, at the transformation temperature Ar3 or more;
    pickling, cold rolling at 20% to 90%;
    heating up to a temperature range of 650 ° C to
    900 ° C;
    annealing for a retention time of 1 second to 300 seconds;
    cooling at a cooling rate of 0.1 ° C / s to 100 ° C / s from 720 ° C to 580 ° C; and galvanizing treatment.
    [22]
    22. Method of producing a galvanized steel sheet according to Claim 21, characterized by the fact that, in the second hot rolling in the temperature range from T1 + 30 ° C to T1 + 200 ° C, the rolling to a lamination reduction ratio of 30% or more in one pass is performed at least once.
    [23]
    23. Production method of a galvanized steel sheet
    Petition 870180044077, of 05/24/2018, p. 133/181
    9/9 according to Claim 21 or 22, characterized in that, in the first hot rolling in the temperature range of 1000 ° C to 1200 ° C, the lamination at a lamination reduction ratio of 20% or more it is performed at least twice, and the diameter of the austenite grain is adjusted to 100 mm or less.
    [24]
    24. Method of producing a galvanized steel sheet according to Claim 21 or 22, characterized in that in a case where the pass in which the lamination reduction ratio is 30% or more in the temperature range of T1 + 30 ° C to T1 + 200 ° C is defined as a large reduction pass, the reduction time t from the end of the final pass of the large reduction pass until the start of cooling uses a configuration that satisfies formula 6, t1 <t <t1 x 2.5 (Formula 6) where t1 is expressed by formula 7 below;
    t1 = 0.001 x ((Tf - T1) x P1) 2 - 0.109 x ((Tf - T1) x P1) + 3.1 ··· (Formula 7) where Tf represents the temperature after the final pass, and P1 represents the ratio of lamination reduction in the final pass.
    [25]
    25. Method of producing a galvanized steel sheet according to Claim 24, characterized by the fact that the temperature of the steel sheet increases by 18 ° C or less between the respective passes of the second hot rolling in the temperature range of T1 + 30 ° C to T1 + 200 ° C.
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    BR112013001864A2|2016-05-31|
    EP2599887B1|2021-12-01|
    JP5163835B2|2013-03-13|
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    CA2806626A1|2012-02-02|
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    US9273370B2|2016-03-01|
    US20130153091A1|2013-06-20|
    TWI439554B|2014-06-01|
    CA2806626C|2016-04-05|
    CN103038383B|2014-12-24|
    TW201213558A|2012-04-01|
    US20160130711A1|2016-05-12|
    MX342629B|2016-10-07|
    KR101514157B1|2015-04-21|
    CN103038383A|2013-04-10|
    EP2599887A4|2017-10-11|
    US9587319B2|2017-03-07|
    KR20130021460A|2013-03-05|
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    法律状态:
    2018-02-27| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|
    2019-01-22| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|
    2019-05-07| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2019-07-02| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 27/07/2011, OBSERVADAS AS CONDICOES LEGAIS. (CO) 20 (VINTE) ANOS CONTADOS A PARTIR DE 27/07/2011, OBSERVADAS AS CONDICOES LEGAIS |
    2019-11-26| B25D| Requested change of name of applicant approved|Owner name: NIPPON STEEL CORPORATION (JP) |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2010169627|2010-07-28|
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