• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:

    公开号:BR112013009515B1
    申请号:R112013009515-6
    申请日:2011-10-21
    公开日:2018-08-07
    发明作者:Tomokiyo Toshimasa；Hayashi Kunio；Aso Toshimitsu
    申请人:Nippon Steel & Sumitomo Metal Corporation；
    IPC主号:
    专利说明:

    (54) Title: METHOD OF MANUFACTURING A HOT PRINTED BODY WITH A VERTICAL WALL AND A HOT PRINTED BODY WITH A VERTICAL WALL (51) Int.CI .: C21D 9/46; C22C 38/00; C22C 38/38; C22C 38/58; C21D 1/18 (30) Unionist Priority: 10/22/2010 JP 2010-237249 (73) Holder (s): NIPPON STEEL & SUMITOMO METAL CORPORATION (72) Inventor (s): TOSHIMASA TOMOKIYO; KUNIO HAYASHI; TOSHIMITSU ASO (85) National Phase Start Date: 04/18/2013
    1/76
    Descriptive Report of the Invention Patent for METHOD OF MANUFACTURING A HOT PRINTED BODY THAT HAS A VERTICAL WALL AND A HOT STAMPED BODY THAT HAS A VERTICAL WALL.
    Field of the Technique [001] The present invention relates to a method for manufacturing a hot stamped body that has a vertical wall and a hot stamped body that has a vertical wall.
    [002] Priority is claimed on Japanese Patent Application No. JP 2010-237249, filed on October 22 , 2010, the contents of which are incorporated into this document by reference. Background to the technique [003] To obtain high strength components of a grade of 1,180 MPa or higher used in automobile components or the like with dimensional accuracy, in recent years, a technology (hereinafter referred to as hot stamping formation) for conferring the high strength of a product formed by heating a steel blade to an austenite strip, pressing it in a high, soft ductile state and then cooling it quickly (tempering) in a press matrix to perform a martensitic transformation was developed.
    [004] In general, a steel sheet used for hot stamping contains a lot of component C to ensure the strength of the product after hot stamping and contains austenite stabilizing elements such as Mn and B to ensure hardness when cooling a matrix. However, although resistance and hardenability are necessary properties for a hot stamped product, when manufacturing a steel sheet that is a material of the same, these properties are disadvantageous in many cases. As a representative disadvantage, with a material that
    Petition 870180043916, of 05/24/2018, p. 4/89
    2/76 has such high hardenability, a hot rolled sheet after a hot rolling step tends to have an uneven microstructure in hot rolling mill locations. Consequently, as a means to resolve the unevenness of the microstructure generated in a dry rolling step, tempering by a batch annealing step after a hot rolling step or a cold rolling step can be considered, however , the batch annealing step generally takes 3 or 4 days and is therefore not preferred from a productivity point of view. In recent years, on normal steel with the exception of a tempering material used for special purposes, from a productivity point of view, it has become common to perform a heat treatment by a continuous annealing step, with the exception of the annealing step per batch.
    [005] However, in the case of the continuous annealing step, since the annealing time is short, it is difficult to perform carbide coalescence to provide softness and uniformity to a steel blade by long time heat treatment such as a treatment per batch. Carbide coalescence is a treatment to provide smoothness and uniformity to the steel blade by maintaining it in the vicinity of an Ac1 transformation point for about several tens of hours. On the other hand, in the case of a short time heat treatment such as the continuous annealing step, it is difficult to ensure the annealing time required for coalescing. That is, in a continuous annealing installation, about 10 minutes is the upper limit as the time to maintain a temperature in the vicinity of Ac1 due to a restriction on an installation extension. In such a short time, since the carbide is cooled before being subjected to coalescence, the steel blade has an uneven microstructure in a hardened state. Such partial variation of the microstructure becomes a
    Petition 870180043916, of 05/24/2018, p. 5/89
    3/76 reason for the variation in the hardness of a hot stamping material, and as a result, as shown in Figure 1, the variation is generated in the strength of the material before heating in a hot stamping step, in many cases.
    [006] Currently, in a hot stamping formation used extensively, it is common to perform quenching at the same time as the press work after heating a steel sheet which is a material for heating in a furnace, and, through heating in a uniform heating furnace at a single austenitic temperature, it is possible to resolve the variation in material strength described above. However, a method of heating a hot stamping material by furnace heating has low productivity since the heating takes a long time. Consequently, a technology for improving the productivity of the hot stamping material by a short time heating method by an electric heating method is disclosed. Through the use of the electric heating method, it is possible to control the temperature distribution of a blade material in a conductive state by modifying the current density that flows into the same blade material (for example, Patent Document 1).
    [007] Additionally, to resolve the variation in hardness, when it heats at a temperature equal to or higher than Ac3 to be a single phase of austenite in an annealing step, a hardened phase such as martensite or bainite is generated in one stage end of the annealing step due to the high hardening due to the effect of Mn or B described above and the hardness of a material increases significantly. Like the hot stamping material, this not only becomes a reason for matrix abrasion on a piece of metal to be stamped, but it also significantly decreases the formability or fixability of the shape of a formed body. Consequently,
    Petition 870180043916, of 05/24/2018, p. 6/89
    4/76 if one considers not only a desired hardness after the hot stamping quench, the formability or the fixability of the shape of a formed body, a preferred material before the hot stamping is a material that is soft and has a variation in small hardness and a material that has an amount of C and hardenability to obtain the desired hardness after hot stamping. However, if manufacturing cost is considered a priority and the manufacture of the steel sheet is assumed in a continuous annealing facility, it is difficult to carry out the control described above by an annealing technology of the related technique.
    [008] Still, in the case of manufacturing a formed body that has a vertical wall by hot stamping, when cooling in a die, a cooling rate in a vertical wall in which a gap in relation to the die is easily generated becomes lower than in a part adhered to the matrix. Consequently, since a variation in the hardness generated during tempering is added in relation to the variation in the hardness in the steel blade before heating in a hot stamping step, there is a problem in which the variation in hardness is generated in the formed body which has the vertical wall.
    List of Citations
    Patent document [009] Patent Document 1 Japanese Patent unexamined, First Application No. JP 2009-274122 [0010] Non - Patent Documents [0011] Non - Patent Document 1 "Iron and Steel Materials", The Japanese Institute of Metals (The Japan Institute of Metals), Maruzen Publishing Co., Ltd. p. 21 [0012] Non-Patent Document 2 Steel Standardization Group, “A Review of the Steel Standardization Group's Method for the Determination of Critical Points of Steel,”
    Petition 870180043916, of 05/24/2018, p. 7/89
    5/76
    Metal Progress, Volume 49, 1946, p. 1169 [0013] Non-Patent Document 3 Yakiiresei (Hardening of steels) - Motomekata to katsuyou (How to obtain and its use) -, (author: OWAKU Shigeo, publisher: Nikkan Kogyo Shimbun)
    Summary of the invention
    Technology Problem [0014] An objective of the present invention is to solve the problems mentioned above and to provide a method of manufacturing a hot stamped body that has a vertical wall and a hot stamped body that has a vertical wall that can suppress the variation in the hardness of a formed body even in the case of manufacturing a formed body that has a vertical wall from a steel sheet for hot stamping.
    Solution to the Problem [0015] An outline of the present invention made to solve the problems mentioned above follows.
    (1) In accordance with a first aspect of the present invention, a method of manufacturing a hot stamped body is provided which includes the steps of:
    hot laminate a plate containing chemical components that include, by weight%, 0.18% to 0.35% C, 1.0% to 3.0% Mn, 0.01% to 1.0% Si, 0.001% to 0.02% P, 0.0005% to 0.01% S, 0.001% to 0.01% N, 0.01% to 1.0% Al, 0.005% to 0.2% Ti, 0.0002% to 0.005% B and 0.002% to 2.0% Cr, and the balance of Fe and unavoidable impurities, to obtain a hot-rolled steel sheet;
    winding the hot-rolled steel sheet that is subjected to hot rolling;
    cold-rolling the rolled hot-rolled steel sheet to obtain a cold-rolled steel sheet;
    continuously anneal the cold-rolled steel sheet that
    Petition 870180043916, of 05/24/2018, p. 8/89
    6/76 is subjected to cold rolling to obtain a steel sheet for hot stamping; and perform hot stamping by heating the steel sheet for hot stamping which is continuously annealed so that a higher heating temperature is equal to or greater than Ac3 ° C, and forming a vertical wall, where continuous annealing includes the steps of: heating the cold-rolled steel sheet to a temperature range equal to or higher than Ac1 ° C and less than Ac 3 ° C;
    cooling the cold rolled steel sheet heated from the highest heating temperature to 660 ° C at a cooling rate equal to or less than 10 ° C / s; and keep the cold-rolled steel sheet cooled in a temperature range of 550 ° C to 660 ° C for one minute to 10 minutes.
    (2) In the method of manufacturing a hot stamped body, according to (1), the chemical components may include one or more from 0.002% to 2.0% of Mo, 0.002% to 2.0% of Nb, 0.002% to 2.0% of V, 0.002% to 2.0% of Ni, 0.002% to 2.0% of Cu, 0.002% to 2.0% of Sn, 0.0005% to 0.0050 % Ca, 0.0005% to 0.0050% Mg, and 0.0005% to 0.0050% REM.
    (3) In the method of manufacturing a hot stamped body, according to (1), any one of a hot dip galvanizing process, a galvanizing and annealing process, a cast aluminum electroplating process, a process of cast aluminum alloy electroplating, and a electroplating process, can be performed after the continuous annealing step.
    (4) In the method of manufacturing a hot stamped body, according to (2), any one of a galvaPetição process 870180043916, of 05/24/2018, p. 9/89
    7/76 hot immersion, a galvanizing and annealing process, a cast aluminum electrodeposition process, a cast aluminum alloy electrodeposition process, and an electroplating process can be performed after the continuous annealing step.
    (5) In accordance with a second aspect of the present invention, a method of manufacturing a hot stamped body is provided which includes the steps of:
    [0016] hot-rolling a plate containing chemical components that include, by weight%, 0.18% to 0.35% C, 1.0% to 3.0% Mn, 0.005% to 1.0 % Si, 0.001% to 0.02% P, 0.001% to 0.01% S, 0.001% to 0.01% N, 0.01% to 1.0% Al, 0.005% to 0 , 2% Ti, 0.0002% to 0.005% B, and 0.002% to 2.0% Cr, and the balance of Fe and unavoidable impurities, to obtain a hot-rolled steel sheet; [0017] to cool the hot-rolled steel sheet that is subjected to hot rolling;
    [0018] cold rolled hot rolled steel sheet to obtain a cold rolled steel sheet;
    [0019] continuously annealing the cold rolled steel sheet which is subjected to cold rolling to obtain a steel sheet for hot stamping; and [0020] perform hot stamping by heating the steel sheet for hot stamping which is continuously annealed so that a higher heating temperature is equal to or greater than Ac3 ° C, and form a vertical wall, [0021 ] where, in hot rolling, in hot finishing laminating configured with a machine with 5 or more consecutive rolling chairs, lamination is carried out by establishing a hot finishing fiT temperature in a rolling mill final Fi in a temperature range of
    Petition 870180043916, of 05/24/2018, p. 10/89
    8/76 (Ac3 - 60) ° C to (Ac 3 + 80) ° C, by establishing a time from the beginning of the rolling in a Fi-3 rolling mill that is a machine prior to the final rolling mill Fi to finalize the lamination in the final laminating plant Fi to be equal to or more than 2.5 seconds and by establishing a hot rolling Fi-3T temperature in the Fi-3 laminating plant to be equal to or less than FiT + 100 ° C and, after maintenance in a temperature range of 600 ° C to Ar3 ° C for 3 seconds to 40 seconds, cooling is performed, [0022] continuous annealing includes the steps of:
    [0023] heat the cold-rolled steel sheet to a temperature range equal to or greater than (Ac1 - 40) ° C and less than Ac 3 ° C;
    [0024] to cool the cold rolled steel sheet heated from the highest heating temperature of 660 ° C in a cooling rate of 10 ° C / s or less; and [0025] keep the cold-rolled steel sheet cooled over a temperature range of 450 ° C to 660 ° C for 20 seconds and 10 minutes.
    (6) In the method of manufacturing a hot-stamped body according to (5), the chemical components may further include one or more from 0.002% to 2.0% Mo, 0.002% to 2.0% Nb , 0.002% to 2.0% of V, 0.002% to 2.0% of Ni, 0.002% to 2.0% of Cu, 0.002% to 2.0% of Sn, 0.0005% to 0.0050% of Ca, 0.0005% to 0.0050% of M and 0.0005% to 0.0050% of REM.
    (7) In the method of manufacturing a hot stamped body, according to (5), any one of a hot-dip galvanizing process, a galvanizing and annealing process, a cast aluminum electroplating process, a process cast aluminum alloy electrodeposition and a process of
    Petition 870180043916, of 05/24/2018, p. 11/89
    9/76 electroplating, can be performed after the continuous annealing step.
    (8) In the method of manufacturing a hot stamped body, according to (6), any one of a hot-dip galvanizing process, a galvanizing and annealing process, a cast aluminum electroplating process, a process of cast aluminum alloy electroplating, and a electroplating process, can be performed after the continuous annealing step.
    (9) In accordance with a third aspect of the present invention, a hot stamped body is provided which is formed using the manufacturing method a hot stamped body according to any of (1) to (8), [0026 ] where when an initial quench temperature is 650 ° C or less, the Vickers DHv hardness range of the hot stamped body is equal to or less than 100, when the initial quench temperature is 650 ° C to 750 ° C, the hardness variation of the hot-stamped body is equal to or less than 60, and when the initial tempering temperature is equal to or higher than 750 ° C, the Vickers DHv hardness variation of the hot-stamped body is the same or less than 40,
    Advantageous Effects of the Invention [0027] According to the methods according to (1) to (8) described above, since the steel sheet in which the physical properties after annealing are uniform and smooth is used, even when manufacturing a formed body that has a vertical wall from such a hot stamped steel blade, it is possible to stabilize the hardness of the hot stamped body.
    [0028] Additionally, through a process of
    Petition 870180043916, of 05/24/2018, p. 12/89
    10/76 hot-dip galvanizing, a galvanizing and annealing process, a cast aluminum electroplating process, a cast aluminum alloy electroplating process, or an electroplating process, after the continuous annealing step, is advantageous, since that it is possible to prevent the generation of scale on a surface, to raise a temperature in a non-oxidizing atmosphere to prevent the generation of scale when raising a hot stamping temperature is unnecessary or a process of removing scale after stamping hot stamping is unnecessary, and also a rust prevention of the hot stamped body is displayed. [0029] Additionally, through the use of such methods, it is possible to obtain a hot stamped body that has a vertical wall in which, when an initial tempering temperature is equal to or lower than 650 ° C, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 100, when the initial tempering temperature is 650 ° C to 750 ° C, the Vicke rs DHv hardness variation of the hot stamped body is equal to or less than 60 and when the initial temperature hardness is equal to or higher than 750 ° C, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 40, Brief Description of the Drawings [0030] Figure 1 is a view showing a variation in the hardness of a steel sheet for hot stamping after continuous annealing of the related technique.
    [0031] Figure 2 is a view showing a temperature history model in a continuous annealing step of the present invention.
    [0032] Figure 3A is a view showing a variation in the hardness of a steel sheet for hot stamping after continuous annealing where a winding temperature is set at 680 ° C.
    Petition 870180043916, of 05/24/2018, p. 13/89
    11/76 [0033] Figure 3B is a view showing a variation in the hardness of a steel sheet for hot stamping after continuous annealing where a winding temperature is set at 750 ° C.
    [0034] Figure 3C is a view showing a variation in the hardness of a steel sheet for hot stamping after continuous annealing where a winding temperature is set at 500 ° C.
    [0035] Figure 4 is a view showing a format of a hot stamped product of the present invention.
    [0036] Figure 5 is a view showing variation in hardness in hot stamping by values of Cr e / CrM and Mn e / MnM in the present invention.
    [0037] Figure 6A is a result of segmented perlite observed by a 2000x SEM.
    [0038] Figure 6B is a result of segmented perlite observed by a 5000x SEM.
    [0039] Figure 7A is a result of non-segmented pearlite observed for 2000x SEM.
    [0040] Figure 7B is a result of non-segmented pearlite observed for 5000x SEM.
    Description of the Modalities [0041] Hereinafter, the preferred modalities of the present invention will be described.
    [0042] First, a method for calculating Ac3 that is important in the present invention will be described. In the present invention, since it is important to obtain an exact value of Ac3, it is desired to measure the value experimentally, instead of calculating from a calculation equation. In addition, it is also possible to measure Ac1 from the same test. As an example of a measurement method, as
    Petition 870180043916, of 05/24/2018, p. 14/89
    12/76 disclosed in Non-Patent Documents 1 and 2, a method to capture from changing the length of a steel blade when heated and cooled is common. At the time of heating, a temperature at which austenite begins to appear is Ac1 and a temperature at which the single phase of austenite appears is Ac3, and it is possible to read each temperature from the change in expansion. In an experimental measurement case, it is common to use a method for heating a steel sheet after cold rolling at a rate of heating on heating in a continuous annealing step, and to measure Ac3 from an expansion curve. The heating rate in this document is an average heating rate in a temperature range of “500 ° C to 650 ° C” which is a temperature equal to or lower than Ac1, and heating is carried out at a constant rate with use of the heating fee.
    [0043] In the present invention, a result measured with the establishment of an increasing temperature rate like 5 ° C / s is used. [0044] Meanwhile, a temperature at which the transformation from a single austenite phase to a low temperature transformation phase such as ferrite or bainite starts is called Ar3, however, regarding the transformation in a hot rolling, Ar3 changes according to hot rolling conditions or a cooling rate after rolling. Consequently, Ar3 is calculated with a calculation model disclosed in ISIJ International, Volume 32 (1992) No. 3, and a maintenance time of Ar3 left at 600 ° C was determined by correlation with an actual have perature.
    [0045] Hereinafter, a steel sheet for hot stamping according to the present invention used in a method of manufacturing a hot stamped body that has a vertical wall will be described.
    Petition 870180043916, of 05/24/2018, p. 15/89
    13/76 (Steel Blade Quench Index for Hot Stamping) [0046] Since it is directed to a hot stamping material to obtain high hardness after quenching, the hot stamping material is generally designed to have a component with high carbon and a component that has high hardenability. In this document, “high hardenability” means that a DI inch value that is a quench index is equal to or greater than 3. It is possible to calculate the sw DI inch value based on ASTM A255-67. A detailed calculation method is shown in Non-Patent Document 3. Several methods of calculating the DIinch value have been proposed, with respect to an equation of fB for calculation using an additive method and for calculating an effect of B, is possible to use an equation of fB = 1 + 2.7 (0.85 -% by weight of C) disclosed in Non-Patent Document 3. Additionally, it is necessary to designate austenite grain size number according to an added amount of C, however, in practice, since the austenite grain size number changes depending on hot rolling conditions, the calculation can be performed by standardizing the grain number to 6. [0047] The DI inch value is one index that shows hardening and is not always connected to the hardness of a steel blade. That is, the hardness of martensite is determined by the amounts of C and other elements of solid solution. Consequently, the problems in this specification do not occur in all steel materials that have a large added amount of C. Even in a case where a large amount of C is included, the phase transformation of a steel blade proceeds relatively quickly. quickly as long as the DIinch value is a low value, and thus the phase transformation is almost complete before rolling in ROT cooling. Still, also in an annealing stage, since the transformation of ferrite proceeds easily in cooling to a temperature
    Petition 870180043916, of 05/24/2018, p. 16/89
    14/76 higher heat, it is easy to manufacture a soft hot stamping material. Meanwhile, the problems of this specification are clearly shown in a steel material that has a high DI inch value and a large added amount of C. Consequently, significant effects of the present invention are obtained in a case where a steel material contains 0, 18% to 0.35% C and the DI inch value is equal to or greater than 3 (7.62 cm). Meanwhile, when the DI inch value is extremely high, since the transformation of ferrite in continuous annealing does not proceed, a value of about 10 (25.4 cm) is preferred as an upper limit of the DI inch value. (Chemical components of the steel sheet for hot stamping) [0048] In the method of manufacturing a hot stamped body that has a vertical wall according to the present invention, a steel sheet for hot stamping manufactured from a steel part that includes chemical components that include C, Mn, Si, P, S, N, Al, Ti, B and Cr and the balance of Fe and unavoidable impurities is used. Additionally, as optional elements, one or more elements among Mo, Nb, V, Ni, Cu, Sn, Ca, Mg and REM can be contained. From now on, a preferential content rate for each element will be described. % indicating the content means% by mass. In the steel sheet for hot stamping, the unavoidable impurities with the exception of the elements described above can be contained as long as their content is a degree that does not significantly affect the effects of the present invention, however, the least possible amount of is preferred.
    (C: 0.18% to 0.35%) [0049] When the C content is less than 0.18%, the hardenability after hot stamping becomes low and the increase in hardness in a component becomes small . Meanwhile, when the
    Petition 870180043916, of 05/24/2018, p. 17/89
    15/76
    C exceeds 0.35%, the formation capacity of the formed body is significantly decreased.
    Consequently, a lower limit value of C is 0.18, preferably 0.20% and more preferably 0.22%. An upper limit value of C is 0.35%, preferably 0.33%, and more preferably 0.30%.
    (Mn: 1.0% to 3.0%) [0051] When the Mn content is less than 1.0%, it is difficult to ensure hardening when hot stamping. Meanwhile, when the Mn content exceeds 3.0%, the Mn segregation occurs easily and cracking occurs easily when hot rolling.
    Consequently, a lower limit value of Mn is 1.0%, preferably 1.2%, and more preferably 1.5%. An upper limit value of Mn is 3.0%, preferably 2.8%, and more preferably 2.5%.
    (Si: 0.01% to 1.0%) [0053] Si has the effect of slightly improving the hardness, however, the effect is light. With Si with a hardening amount of solid solution compared to other elements contained, it is possible to reduce the amount of C to obtain the desired hardness after quenching. Consequently, it is possible to contribute to an improvement in welding capacity, which is a disadvantage of steel that has a large amount of C. Consequently, the effect of the same when the added amount is large, however, when the added amount of it exceeds 0 , 1%, due to the generation of oxides from the steel blade, the chemical conversion coating to confer corrosion resistance is significantly degraded or the galvanization wettability is disturbed. Additionally, a lower limit is
    Petition 870180043916, of 05/24/2018, p. 18/89
    16/76 particularly supplied, however, about 0.01%, which is an amount of Si used at a normal deoxidation level, is a practical lower limit.
    [0054] Consequently, the lower limit value of Si is 0.01%. The upper limit value of Si is 1.0%, and preferably 0.8%.
    (P: 0.001% to 0.02%) [0055] P is an element that has a hardening property of high solid solution, however, when its content exceeds 0.02%, the chemical conversion coating is degraded from same as in the case of Si. In addition, a lower limit is not particularly provided, however, it is difficult to have a content less than 0.001% since the cost increases significantly.
    (S: 0.0005% to 0.01%) [0056] Since S generates inclusions such as MnS that degrades robustness or workability, it is desired that the added amount of it is small. Consequently, the amount thereof is preferably less than or equal to 0.01%. Additionally, a lower limit is not provided, however, it is difficult to have a content less than 0.0005% since the cost increases significantly.
    (N: 0.001% to 0.01%) [0057] Since N degrades the effect to improve hardenability with the addition of B, it is preferable to have an extremely small amount added. From that point of view, the upper limit is set at 0.01%. Additionally, the lower limit is not provided, however, it is difficult to have a content lower than 0.001% as the cost increases significantly.
    (Al: 0.01% to 1.0%) [0058] Since Al has the hardening property of solid solution in the same way as Si, it can be added to reduce the added amount of C. since Al degrades the coating
    Petition 870180043916, of 05/24/2018, p. 19/89
    17/76 of chemical conversion or wettability of galvanization in the same way as Si, the upper limit of it is 1.0% and the lower limit is not provided, however, 0.01%, which is the amount of Al mixed at the deoxidation level, it is a practical lower limit.
    (Ti: 0.005% to 0.2%) [0059] Ti is advantageous for detoxifying N, which degrades the effect of adding B. That is, when the N content is large, B is bound to N, and BN is formed. Since the effect to improve the hardness of B is exhibited at the time of a solid solution state of B, although B is added in a state of large amount of N, the effect to improve the hardness is not obtained. Consequently, with the addition of Ti, it is possible to fix N as TiN and allow B to remain in a solid solution state. In general, the amount of Ti needed to achieve this effect can be obtained by adding the amount that is approximately four times the amount of N in an atomic weight ratio. Consequently, when considering the N content inevitably mixed, a content equal to or greater than 0.005%, which is the lower limit, is necessary. Additionally, Ti is linked to C and TiC is formed. Since an effect to improve a delayed fracture property after hot stamping can be obtained, when the delayed fracture property is actively improved, it is preferable to add 0.05% or more of Ti. However, if an added amount exceeds 0.2%, coarse TiC is formed in a margin of austenite grain or the like and cracks are generated in hot rolling, so that 0.2% is established as the upper limit.
    (B: 0.0002% to 0.005%) [0060] B is one of the most efficient elements as an element to improve hardenability at a low cost. As described above, when adding B, since it is necessary to be in a
    Petition 870180043916, of 05/24/2018, p. 20/89
    18/76 state of solid solution, it is necessary to add Ti, if necessary. Additionally, since the effect of the same is not obtained when the amount of the same is less than 0.0002%, 0.0002% is established as the lower limit. Meanwhile, since its effect becomes saturated when the amount of it exceeds 0.005%, it is preferable to set 0.005% as the upper limit.
    (Cr: 0.002% to 2.0%) [0061] Cr improves hardenability and robustness with a content equal to or greater than 0.002%. The improvement in robustness is obtained through an effect to improve the delayed fracture property by forming carbide alloy or an effect to refine grain the size of the austenite grain. Meanwhile, when the Cr content exceeds 2.0%, its effects become saturated.
    (Mo: 0.002% to 2.0%) (Nb: 0.002% to 2.0%) (V: 0.002% to 2.0%) [0062] Mo, Nb, and V improve hardenability and toughness with a content equal to or greater than 0.002%, respectively. The effect to improve the robustness can be obtained through the improvement of the delayed fracture property by formation of alloy carbide or by grain refinement of the austenite grain size. Meanwhile, when the content of each element exceeds 2.0%, their effects become saturated. Consequently, the amounts contained in Mo, Nb and V can be in the range of 0.002% to 2.0%, respectively.
    (Ni: 0.002% to 2.0%) (Cu: 0.002% to 2.0%) (Sn: 0.002% to 2.0%) [0063] Additionally, Ni, Cu and Sn improve strength with an equal content or greater than 0.002%, respectively. Meanwhile, when the content of each element exceeds 2.0%, their effects become
    Petition 870180043916, of 05/24/2018, p. 21/89
    19/76 saturated. Consequently, the amounts contained in Ni, Cu and Sn can be in the range of 0.002% to 2.0%, respectively.
    (Ca: 0.0005% to 0.0050%) (Mg: 0.0005% to 0.0050%) (REM: 0.0005% to 0.0050%) [0064] Ca, Mg and REM have effects of grain refinement of inclusions with each content equal to or greater than 0.0005% and their suppression. Meanwhile, when the amount of each element exceeds 0.0050%, their effects become saturated. Consequently, the amounts contained in Ca, Mg and REM can be in the range of 0.0005% to 0.0050%, respectively.
    (Microstructure of the steel sheet for hot stamping) [0065] Next, a microstructure of the steel sheet for hot stamping will be described.
    [0066] Figure 2 shows a model of temperature history in the continuous annealing step. In Figure 2, Ac1 signifies a temperature at which the reverse transformation to austenite begins to occur at the time of temperature rise, and Ac3 signifies a temperature at which a metal composition of the steel blade becomes completely austenite at the time of elevation. temperature. The steel sheet subjected to the hot rolling step is in a state in which the microstructure of the cold rolled sheet is crushed by cold rolling, and in that state, the steel sheet is in a hardened state with extremely high displacement density. high. In general, the microstructure of the hot-rolled steel sheet of the tempering material is a mixed structure of ferrite and perlite. However, the microstructure can be controlled for a structure formed mainly of martensite by a hot rolled blade winding temperature. As will be described later, in the factory Petition 870180043916, of 05/24/2018, p. 22/89
    20/76 tion of the steel sheet for hot stamping, by heating the steel sheet equal to or greater than Ac1 ° C in a heating step, a volume fraction of non-recrystallized ferrite is set to be equal to or less than 30 %. Additionally, by setting the highest heating temperature to be less than Ac3 ° C in the heating step and by cooling from the highest heating temperature to 660 ° C at a cooling rate equal to or less than 10 ° C / s in the cooling stage, the ferrite transformation proceeds with cooling and the steel blade is softened. When, in the cooling stage, the transformation of ferrite is promoted and the steel sheet is softened, it is preferable that the ferrite remains slightly in the heating stage, and, consequently, it is preferable to establish the highest heating temperature to be “( Aci + 20) ° C to (Ac3 - 10) ° C. By heating in this temperature range, in addition, the hardened non-recrystallized ferrite is softened by recovery and recrystallization due to the displacement movement at annealing, it is possible to austenitize the remaining hardened non-recrystallized ferrite. In the heating step, the non-recrystallized ferrite remains slightly in a subsequent cooling step at a cooling rate equal to or less than 10 ° C / s and a maintenance step to maintain a temperature range of “550 ° C to 660 ° C ”for 1 minute to 10 minutes, the ferrite grows through the nucleation of the non-recrystallized ferrite and the precipitation of cementite is promoted by the concentration of C in the untransformed austenite. Consequently, the main microstructure after the annealing step of the steel sheet for hot stamping according to the modality is configured of ferrite, cementite and perlite, and contains a part of the remaining austenite, martensite and bainite. The highest heating temperature range in the heating stepPetition 870180043916, 05/24/2018, pg. 23/89
    21/76 cement can be expanded by adjusting rolling conditions in the hot rolling stage and cooling conditions in ROT. That is, the problem factor originates in the variation of the microstructure of the hot-rolled sheet and if the microstructure of the hot-rolled sheet is adjusted so that the hot-rolled sheet is homogenized and the recrystallization of the ferrite after the cold rolling proceeds evenly and quickly, although the lower limit of the highest heating temperature in the heating step is expanded to (Ac1 - 40) ° C, it is possible to suppress the remainder of the non-recrystallized ferrite and expand the conditions in the maintenance step (as will be described later, in a temperature range of “450 ° C to 660 ° C” for 20 seconds to 10 minutes).
    [0067] In more detail, the steel sheet for hot stamping includes a metal structure in which a volume fraction of the ferrite obtained by combining the recrystallized ferrite and the transformed ferrite is equal to or greater than 50%, and a fraction of volume of the non-recrystallized ferrite fraction is equal to or less than 30%. When the ferrite fraction is less than 50%, the strength of the steel blade after the continuous annealing step becomes hard. In addition, when the fraction of the non-recrystallized ferrite exceeds 30%, the hardness of the steel blade after the continuous annealing step becomes hard.
    [0068] The ratio of the non-recrystallized ferrite can be measured by analysis in a Backscattered Electron Diffraction (EBSP). The breakdown of non-recrystallized ferrite and other ferrite, that is, recrystallized ferrite and transformed ferrite, can be performed by analysis of EBSP crystalline orientation measurement data using the Mean Disorientation Kernel Method (KAM method). The displacement is recovered in the non-recrystallized ferrite grains, however, the continuous change in the crystalline orientation generated due to plastic deformation at the time of cold rolling exists. Meanwhile, changing the
    Petition 870180043916, of 05/24/2018, p. 24/89
    22/76 crystalline orientation in ferrite grains with the exception of non-recrystallized ferrite is extremely small. This is because, although the crystalline orientation of the adjacent crystalline grains is quite different due to recrystallization and transformation, the crystalline orientation in a crystal grain is not changed. In the KAM method, since it is possible to quantitatively show the difference in crystalline orientation of adjacent pixels (measurement points), in the present invention, in the definition of the grain margin between a pixel in which a difference in average crystalline orientation with the measurement point adjacent is within 1 ° (degree) and a pixel in which the difference in average crystalline orientation with the adjacent measurement point is equal to or greater than 2 ° (degrees), the grain having a crystalline grain size equal to or greater than 3 pm is defined as ferrite instead of non-recrystallized ferrite, that is, recrystallized ferrite and transformed ferrite.
    [0069] In addition, the steel blade for hot stamping (A) a value of ratio Cr and / CRM concentration Cr and Cr subjected to the solid solution of iron carbide and Cr CRM concentration subjected to the solid solution a base material is equal to or less than 2, or (B) a value of an Mn e / MnM ratio of Mn and Mn concentration submitted to the solid solution in iron carbide and MnM concentration of Mn submitted to the solid solution in a material base is less than or equal to 10.
    [0070] Cementite, which is representative of iron carbide, is dissolved in austenite at the time of heating the hot stamping, and the concentration of C in austenite is increased. At the time of heating in a hot stamping step, when heating in a low temperature for a short time through rapid heating or the like, dissolving cementite is not sufficient and the hardness or hardness after tempering is not sufficient. A cementite dissolution rate can be improved by reducing a
    Petition 870180043916, of 05/24/2018, p. 25/89
    23/76 amount of Cr or Mn distribution which is an element easily distributed in cementite, in cementite. When the Cr e / CrM value exceeds 2 and the Mn e / MnM value exceeds 10, the dissolution of cementite in austenite at the time of heating for a short time is insufficient. It is preferable that the value of Cr e / CrM is equal to or less than 1.5 and the value of Mn and / MnM is equal to or less than 7.
    [0071] Cre / CrM and Mn and / MnM can be reduced by the method to manufacture a steel blade. As will be described in detail, it is necessary to suppress the diffusion of substitute elements in the iron carbide, and it is necessary to control the diffusion in, and the continuous annealing step after cold rolling. Substitute elements such as Cr or Mn are different from interstitial elements such as C or N, and diffuse into iron carbide and are retained at a high temperature equal to or greater than 600 ° C for a long time. To avoid this, there are two main methods. One is a method for dissolving all austenite by heating the iron carbide generated in the hot rolling to Ac1 to Ac3 in continuous annealing and to perform slow cooling from the highest heating temperature to a temperature equal to or less than 10 ° C / retaining at 550 ° C to 660 ° C to generate the transformation of ferrite and iron carbide. Since the iron carbide generated by continuous annealing is generated in a short time, it is difficult for the substitute elements to diffuse. [0072] In the other one, in the cooling stage after the hot rolling stage, by completing the transformation of perlite and ferrite, it is possible to confer a soft and uniform state in which a diffusion proportion of the substitute elements in the carbide iron in the pearlite is small. The reason for limiting hot rolling conditions will be described later. Consequently, in the state of the hot-rolled sheet after hot rolling, it is possible to set the values of Cr e / CrM and Mn and / MnM as low values.
    Petition 870180043916, of 05/24/2018, p. 26/89
    24/76
    Therefore, in the continuous annealing step after cold rolling, even with annealing in a temperature range of (AC1 40) ° C in which only recrystallization of the hollow ferrite, if it is possible to complete the transformation in the cooling of ROT after hot rolling, Cr e / CrM and Mn e / MnM can be set to be low.
    [0073] As shown in Figure 5, the threshold values were determined from an expansion curve when C-1 is retained where the values of Cr e / CrM and Mn and / MnM are low and C-4 where the values of Cr e / CrM and Mn e / MnM are high, for 10 seconds after heating to 850 ° C at 150 ° C / s, and then cooling to 5 ° C / s. That is, while the transformation starts close to 650 ° C on cooling, in a material where the values of Cr e / CrM and Mn and / MnM are high, the transparent phase transformation is not observed at a temperature equal to or less than 400 ° C, in the material where the Cre / CrM and Mn and / MnM values are high. That is, by setting the Cre / CrM and Mn and / MnM values to be low, it is possible to improve the hardness after rapid heating.
    [0074] A method of measuring Cr and Mn component analysis in iron carbide is not particularly limited, however, for example, the analysis can be performed with an energy diffusion spectrometer (EDS) attached to a TEM, making replica materials are extracted from arbitrary locations of the steel blade and observed using the transmission electron microscope (TEM) with a magnification of 1,000 or more. Additionally, for Cr and Mn component analysis in a parental phase, the EDS analysis can be performed on ferrite grains sufficiently separated from the iron carbide, making a thin film generally used.
    [0075] Additionally, on the steel sheet for hot stamping, a fraction of the non-segmented perlite can be equal to or more
    Petition 870180043916, of 05/24/2018, p. 27/89
    25/76 than 10%. The non-segmented perlite shows that the perlite that is austenized once in the annealing step is transformed to the perlite again in the cooling step, the non-segmented perlite shows that the values of Cr e / CrM and Mn and / MnM are lower.
    [0076] If the fraction of the non-segmented pearlite is equal to or more than 10%, the hardness of the steel blade is improved.
    [0077] When the microstructure of the hot-rolled steel sheet is formed from ferrite and perlite, if the ferrite is recrystallized after the cold rolling of the hot-rolled steel sheet to about 50%, generally, the location which indicates that the non-segmented perlite is in a state in which the perlite is finely segmented, as shown in the result observed by the SEM of Figures 6A and 6B. On the other hand, when the heating in the continuous annealing to be equal to or greater than Ac1, after the perlite is austenized once, by the cooling and subsequent maintenance step, the ferrite transformation and the perlite transformation occur. Since the perlite is formed by transformation for a short time, the perlite is in a state that does not contain the substitute elements in the iron carbide and has a non-segmented shape as shown in Figures 7A and 7B.
    [0078] A non-segmented perlite area ratio can be obtained by observing a polished and cut test piece with an optical microscope and measuring the ratio using a point counting method.
    (First Mode) [0079] Later in the present document, a method for manufacturing a hot stamped body that has a vertical wall according to a first embodiment of the present invention will be described.
    [0080] The method for making a hot stamped body that
    Petition 870180043916, of 05/24/2018, p. 28/89
    26/76 has a vertical wall according to the modality includes at least one hot rolling step, a winding step, a cold rolling step, a continuous annealing step and a hot stamping step. Later in this document, each step will be described in detail.
    (Hot rolling step) [0081] In the hot rolling step, a steel piece that has the chemical components described above is heated (reheated) to a temperature equal to or greater than 1,100 ° C, and the hot rolling is realized. The steel part can be a sheet obtained immediately after being manufactured by a continuous casting facility or it can be manufactured using an electric furnace. By heating the steel part to a temperature equal to or greater than 1. 100 ° C, carbide and carbon forming elements can be subjected to dissolution by sufficient decomposition in the steel material. In addition, by heating the steel part to a temperature equal to or greater than 1,200 ° C, the precipitated carbonitrides in the steel part can be sufficiently dissolved. However, it is not preferable to heat the steel part to a temperature above 1,280 ° C, from a production cost point of view.
    [0082] When a finishing temperature of the hot rolling mill is less than Ar3 ° C, the transformation of ferrite takes place in rolling through the contact of the surface layer of the steel blade and a mill roll and rolling resistance of the rolling mill can be significantly high. The upper threshold of the finishing temperature is not particularly provided, however, the upper threshold can be set to about 1,050 ° C.
    (Winding Step) [0083] It is preferable that a winding temperature in the winding step after the hot rolling step is a range
    Petition 870180043916, of 05/24/2018, p. 29/89
    27/76 temperature from “700Ό to 90050” (transformation range of ferrite and transformation of pearlite) or in a temperature range of “25 ° C to 500 ° C” (transformation range of martensite or bainite transformation) ). In general, since the winding after winding is cooled from the edge portion, the cooling history becomes irregular, and as a result, the microstructure irregularity occurs easily, however, by cooling the hot rolled winding in the temperature range described above, it is possible to suppress the occurrence of irregularity of the microstructure in the hot rolling step. However, even with a winding temperature beyond the preferred range, it is possible to reduce its significant variation compared to the related technique by controlling the microstructure in continuous annealing.
    (Cold Rolling Stage) [0084] In the cold rolling stage, the rolled hot rolled steel sheet is cold rolled after pickling, and a cold rolled steel sheet is manufactured.
    (Continuous annealing step) [0085] In the continuous annealing step, the cold-rolled steel sheet is subjected to continuous annealing. The continuous annealing step includes a heating step for heating the cold-rolled steel sheet in a temperature range equal to or greater than “Ac1 ° C and less than Ac3 ° C”, and a cooling way subsequent cold-rolled steel blade to 660 ° C from the highest heating temperature setting a cooling rate to 10 ° C / s or less, and a subsequent maintenance step of the rolled steel blade cold in a temperature range of “550 ° C to 660 ° C” for 1 minute to 10 minutes.
    (Hot stamping step)
    Petition 870180043916, of 05/24/2018, p. 30/89
    28/76 [0086] In the hot stamping step, hot stamping is performed for the steel sheet that is subjected to continuous annealing as described above after heating to a temperature equal to or greater than Ac3 and a vertical wall is formed. In addition, the vertical wall means a portion that is parallel to a press direction, or a portion that intersects with a press direction at an angle within 20 degrees. The general conditions can be used for the heating rate or the subsequent cooling rate. However, since production efficiency is extremely low at a heating rate of less than 3 ° C / s, the heating rate can be set to be equal to or more than 3 ° C / s. Additionally, since the vertical wall may not be sufficiently cooled in particular, at a cooling rate of less than 3 ° C / s, the cooling rate can be set to be equal to or more than 3 ° C / s.
    [0087] The heating method is not particularly regulated and, for example, a method for performing electric heating or a method for using a heating furnace can be employed. [0088] The upper threshold for the highest heating temperature can be set to 1,000 ° C. In addition, maintenance at the highest heating temperature may not be performed, since it is not necessary to provide a particular maintenance time since the reverse transformation to the single austenite phase is obtained.
    [0089] According to the method for manufacturing a hot stamped body described above, since the steel sheet for hot press where the hardness is uniform and which is soft is used, even in a case of forming by of the formed body that has a vertical wall in which the gap with the die is easily generated, it is possible to reduce the variation in the hardness of the hot stamped body. In
    Petition 870180043916, of 05/24/2018, p. 31/89
    29/76 details, it is possible to obtain a formed body that has a vertical wall in which, when a tempering start temperature is equal to or less than 650 ° C, the variation of the Vickers DHv hardness of the hot stamped body is equal a or less than 100, when the tempering start temperature is 650 ° C to 750 ° C, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 60, and when the tempering start temperature is equal to or greater than 750 ° C, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 40.
    [0090] The steel sheet for hot stamping contains a batch of C component to ensure the hardness of quench after hot stamping and contains Mn and B, and in such steel component that has high hardenability and high concentration of C , the microstructure of the hot rolled blade after the hot rolling step tends to become irregular easily. However, according to the method for making the cold rolled steel sheet for hot stamping according to the modality, in the continuous annealing step subsequent to the last stage of the cold rolling step, the cold rolled steel sheet is heated in a temperature range of “equal to or greater than Ac1 ° C and less than Ac3 ° C”, then cooled from the highest temperature to 660 ° C at a cooling rate equal to or less than 10 ° C / s , and then retained in a temperature range of “550 ° C to 660 ° C” for 1 minute to 10 minutes and, therefore, the microstructure can be obtained to be uniform.
    [0091] In the continuous annealing line, a hot dip galvanizing process, a galvanizing and annealing process, a cast aluminum electroplating process, a cast aluminum alloy electroplating process, and a electroplating process can be accomplished. The effects of the present invention
    Petition 870180043916, of 05/24/2018, p. 32/89
    30/76 are not lost even when the electrodeposition process is carried out after the annealing step.
    [0092] As shown in the schematic view of Figure 2, the microstructure of the steel sheet submitted to the cold rolling step is a non-recrystallized ferrite. In the method of manufacturing a hot stamped body that has a vertical wall according to the modality, in the continuous annealing step, heating for a heating range “equal to or greater than Ac1 ° C and less than Ac 3 ° C ”, which is a temperature range higher than the point Ac1, heating is carried out until it has a double phase coexistence with the austenite phase in which the non-recrystallized ferrite remains slightly. After that, in the cooling step at a cooling rate equal to or less than 10 ° C / s, the growth of the transformed ferrite that is nucleated from the non-recrystallized ferrite that remains slightly at the highest heating temperature occurs. Then, in the maintenance step of maintaining the steel blade in a temperature range of “550 ° C to 660 ° C” for 1 minute to 10 minutes, the thickening of C in the untransformed austenite occurs at the same time as the transformation of ferrite, and precipitation of cementite or transformation of perlite is promoted by retaining it in the same temperature range. [0093] The steel sheet for hot stamping contains a batch of C component to ensure the quenching hardness after hot stamping and contains Mn and B, and B has an effect of suppressing the generation of ferrite nucleation at the moment of austenite single-phase cooling, generally, and when cooling is performed after heating to the single-phase austenite range equal to or greater than Ac3, it is difficult for ferrite transformation to occur. However, by retaining the heating temperature in the continuous annealing step in a temperature range “equal to or greater than Ac1 ° C and less than Ac3 ° C” which is immediately below Ac 3, the ferrite remains
    Petition 870180043916, of 05/24/2018, p. 33/89
    31/76 slightly in a state where non-recrystallized, almost hardened ferrite is transformed inversely into austenite, and in the subsequent cooling step at a cooling rate equal to or less than 10 ° C / s and the maintenance maintenance step in a range temperature from “550 ° C to 660 ° C” for 1 minute to 10 minutes, softening is carried out by the growth of ferrite through the nucleation of the remaining ferrite. In addition, if the heating temperature in the continuous annealing step is higher than Ac3 ° C, since the single austenite phase occurs mainly, and then the transformation of ferrite on cooling is insufficient, and the hardening is checked, the temperature described above it is established as the upper threshold, and if the heating temperature is below Ac1, since the volume fraction of the non-recrystallized ferrite becomes high and the hardening is checked, the temperature described above is established as the lower limit.
    [0094] Additionally, in the maintenance step of maintaining the cold-rolled steel blade in a temperature range of “550 ° C to 660 ° C” for 1 minute to 10 minutes, the precipitation of cementite or the transformation of perlite it can be promoted in the unprocessed austenite in which C is thickened after the transformation of ferrite. Therefore, according to the method to manufacture a formed body that has a vertical wall according to the modality, even in a case of heating a material that has high hardenability to a temperature just below the point of Ac3 by continuous annealing, the most parts of the microstructure of the steel blade can be established as ferrite and cementite. According to the state of further processing, bainite, martensite, and the remaining austenite exist slightly after cooling, in some cases.
    [0095] Additionally, if the temperature in the maintenance step
    Petition 870180043916, of 05/24/2018, p. 34/89
    32/76 exceeds 660 ° C, further processing of ferrite is delayed and annealing takes a long time. On the other hand, when the temperature is below 550 ° C, the ferrite that is generated by the transformation is hardened, it is difficult for cementite precipitation or the transformation of perlite to proceed, or the bainite or martensite that is the product of lower temperature transformation occurs. In addition, when the maintenance time exceeds 10 minutes, the continuous annealing installation subsequently becomes longer and the high cost is necessary, and on the other hand, when the maintenance time is less than 1 minute, the transformation of ferrite, the precipitation of cementite, or the transformation of perlite is insufficient, the structure is formed mainly of bainite or martensite in which most parts of the microstructure after cooling are hardened, and the steel blade is hardened.
    [0096] According to the manufacturing method described above, cooling the hot rolled winding submitted to the hot rolling step in a temperature range of "700 ° C to 900 ° C" (ferrite or perlite range) , or by cooling in a temperature range of “25 ° C to 550 ° C” which is a low temperature transformation temperature range, it is possible to suppress the microstructure irregularity of the hot-rolled winding after winding. That is, close to the temperature of 600 ° C in which normal steel is generally wound, it is a temperature range in which the transformation of ferrite and the transformation of perlite occurs, however, when the type of steel that has high hardenability is wound. in the same temperature range after establishing the conditions of the normally performed hot rolling finish, since almost no transformation takes place in a section of cooling device that is called the Exit Table (later in this document, ROT) from laPetição 870180043916, of 05/24/2018, p. 35/89
    33/76 When finishing the hot rolling step for the winding, the phase transformation of the austenite occurs after the winding. Consequently, when considering the direction of the winding width, the rate of cooling in the edge portion exposed to the outside air and the shielded center portion of the outside air are different from each other. In addition, also in the case of considering a longitudinal direction of the winding, in the same way as described above, the cooling histories at a tip end or a posterior end of the winding that may be in contact with the outside air and in a shielded intermediate portion of the outside air are different from each other. Consequently, in the component that has high hardenability, when it rolls over a temperature range in the same way as in a case of normal steel, the microstructure or hardness of the hot-rolled blade varies significantly in a winding due to the difference in history cooling. When annealing is carried out by the continuous annealing installation after a cold rolling with the use of a hot-rolled sheet, in the ferrite recrystallization temperature range equal to or less than Ac1, the significant variation in hardness is generated as shown in Figure 1 by the variation in the rate of ferrite recrystallization caused by the variation of the microstructure of the hot-rolled sheet. Meanwhile, it almost heats up to the temperature range equal to or greater than Ac1 and cools as it stands, not only does a batch of non-recrystallized ferrite remain, but the austenite that is partially inversely transformed is transformed into bainite or martensite which is a hardened phase, and becomes a hard material that has significant variation in hardness. When heated to a temperature equal to or greater than Ac3 to completely remove the non-recrystallized ferrite, significant hardening is carried out after cooling with an effect of elements to improve the hardness such as Mn or
    Petition 870180043916, of 05/24/2018, p. 36/89
    34/76
    B. Consequently, it is advantageous to perform the winding in the temperature range described above for uniformity of the microstructure of the hot-rolled blade. That is, by performing the winding in the winding in the temperature range of “700 ° C to 900 ° C”, this means that the cooling is sufficiently pre-formed from the high temperature state after the winding, it is possible to form the entire winding with the ferrite / perlite structure. Meanwhile, cooling in the temperature range of “25 ° C to 550 ° C”, it is possible to form the entire winding in bainite or martensite which is hard.
    [0097] Figures 3A to 3C show the variation in strength of the steel sheet for hot stamping after continuous annealing with different winding temperatures for the hot rolled winding. Figure 3A shows a case of continuous annealing with a winding temperature of 680 ° C, Figure 3B shows a case of continuous annealing with a winding temperature of 750 ° C, that is, in the temperature range of “700 ° C to 900 ° C” (ferrite transformation and perlite transformation range), and Figure 3C shows a case of continuous annealing, establishing a winding temperature as 500 ° C, that is, in the temperature range of “25 ° C to 500 ° C” (range of transformation of bainite and transformation of martensite). In Figures 3A to 3C, ATS indicates the variation in strength of the steel blade (maximum value of tensile strength of the steel blade - minimum value of the same). As shown clearly in Figures 3A to 3C, by performing continuous annealing with suitable conditions, it is possible to obtain smooth and uniform hardness of the steel blade after annealing, and consequently, it is possible to reduce the variation in the hardness of the hot stamped body that has a vertical wall.
    [0098] With the use of steel that has uniform hardness, in the
    Petition 870180043916, of 05/24/2018, p. 37/89
    35/76 hot stamping, even in a case of manufacture of the formed body that has the vertical wall in which the cooling rate easily becomes slower than in other parts, it is possible to stabilize the hardness of a component of the formed body after the hot stamping. Additionally, for the portion that is an electrode retention portion in which the temperature does not increase through electrical heating and in which the material hardness of the steel blade itself affects the product's hardness, uniformly managing the material's hardness. steel blade itself, it is possible to improve the precision management of the product quality of the body formed after hot stamping.
    (Second Mode) [0099] Later in the present document, a method for manufacturing the hot stamped body that has a vertical wall according to a second embodiment of the present invention will be described.
    [00100] The method for making a hot stamped body according to the modality includes at least one hot rolling step, a rolling step, a cold rolling step, a continuous annealing step and a stamping step hot. Later in this document, each step will be described in detail.
    (Hot rolling step) [00101] In the hot rolling step, a steel piece that has the chemical components described above is heated (reheated) to a temperature equal to or greater than 1,100 ° C, and the hot rolling is realized. The steel part can be a sheet obtained immediately after being manufactured by a continuous casting facility or it can be manufactured using an electric furnace. When the steel part is heated to a temperature equal to or greater than 1,100 ° C, the
    Petition 870180043916, of 05/24/2018, p. 38/89
    36/76 carbide and carbon forming elements can be dissolved by decomposition sufficiently in the steel material. In addition, by heating the steel part to a temperature equal to or greater than 1,200 ° C, the precipitated carbonitrides in the steel part can be sufficiently dissolved. However, it is not preferable to heat the steel part to a temperature above 1,280 ° C, from a production cost point of view. In the hot rolling stage of the modality, in finishing hot rolling configured with a machine with 5 or more consecutive rolling chairs, lamination is carried out (A) by establishing a hot finishing temperature of FT finishing in a plant final rolling mill Fi in a temperature range of (Ac3 - 80) ° C to (Ac 3 + 40) ° C, (B) establishing a moment of lamination start in a Fi-3 rolling mill which is a machine prior to the final rolling mill Fi at the end of the rolling mill at the final rolling mill Fi to be equal to or longer than 2.5 seconds, and (C) establishing a hot rolling temperature Fi-3T at the Fi-3 lamination to be equal to or less than (FiT + 100) ° C, and then maintenance is performed in a temperature range of “600 ° C to Air 3 ° C” for 3 seconds to 40 seconds, and the winding is carried out in the winding step.
    [00102] Through the realization of such hot lamination, it is possible to carry out the stabilization and transformation of austenite to ferrite, perlite, or bainite which is the low temperature transformation phase in the ROT (Exit Table) which is a cooling bed in hot rolling, and it is possible to reduce the variation in the hardness of the steel blade accompanied by a deviation of the cooling temperature generated after the winding of the winding. In order to complete the transformation in the ROT, the refinement of the austenite grain size and maintenance at a temperature equal to or less than Ar3 ° C in the ROT for a long time are important conditions.
    Petition 870180043916, of 05/24/2018, p. 39/89
    37/76 [00103] When F, T is less than (AC3 - 80) ° C, a possibility of ferrite transformation in hot rolling becomes high and the resistance to deformation of hot rolling is not stabilized. On the other hand, when the FT is greater than (AC3 + 40) ° C, the austenite grain size immediately before cooling after the finishing hot rolling becomes coarse and the transformation of ferrite is delayed. It is preferable that the FT is established as a temperature range from “(AC3 - 70) ° C to (Ac 3 + 20) ° C”. By establishing the heating conditions as described above, it is possible to refine the austenite grain size after finishing lamination and it is possible to promote the transformation of ferrite in the cooling of ROT. Consequently, since the transformation proceeds in the ROT, it is possible to greatly reduce the variation of the microstructure in the longitudinal and width directions of the winding caused by the variation in winding cooling after winding. [00104] For example, in a case of a hot rolling mill line that includes seven final rolling mills, transit time of an F4 rolling mill that corresponds to a third plant of an F7 rolling mill that is a final platform , for the F7 rolling mill is set at 2.5 seconds or more. When the transit time is less than 2.5 seconds, since austenite is not recrystallized between platforms, B segregated to the austenite grain margin significantly delays the transformation of ferrite and is difficult for the phase transformation in ROT proceed. The transit time is preferably equal to or longer than 4 seconds. It is not particularly limited, however, when the transition time is equal to or longer than 20 seconds, the temperature of the steel blade between the platforms decreases to a large extent and it is impossible to perform hot rolling.
    [00105] To recrystallize so that austenite is refined and B
    Petition 870180043916, of 05/24/2018, p. 40/89
    38/76 does not exist in the austenite grain margin, it is necessary to complete the lamination at an extremely low temperature equal to or greater than Ar3, and to recrystallize austenite in the same temperature range. Consequently, the temperature on the lamination outlet side of the F4 rolling mill is set to be equal to or less than (FiT + 100) ° C. This is because it is necessary to lower the temperature of the lamination temperature of the F4 rolling mill to obtain a refinement effect of the austenite grain size in the last stage of the finishing lamination. The lower limit of Fi-3T is not provided particularly, however, since the temperature on the outlet side of the F7 final rolling mill is FiT, this is established as the lower limit of the same.
    [00106] Establishing the maintenance time in the temperature range of 600 ° C to Ar3 ° C to be a long time, the transformation of ferrite occurs. Since Ar3 is the starting temperature for ferrite transformation, this is set as the upper threshold, and 600 ° C at which the softened ferrite is generated is set as the lower threshold. A preferred temperature range is 600 ° C to 700 ° C, where ferrite transformation generally proceeds more quickly. (Winding Step) [00107] By maintaining the winding temperature in the winding step after the hot rolling step at 600 ° C to Ar3 ° C for 3 seconds or more in the cooling step, the steel sheet laminated to in which the ferrite transformation continued, it is wound in the same way. Substantially, although it is changed by the installation length of the ROT, the steel sheet is wound in the temperature range of 500 ° C to 650 ° C. By carrying out the hot rolling described above, the microstructure of the hot rolled blade after winding cooling has a structure that mainly includes ferrite and perlite, and it is possible to suppress the irregularity
    Petition 870180043916, of 05/24/2018, p. 41/89
    39/76 of the microstructure generated in the hot rolling stage.
    (Cold Rolling Step) [00108] In the cold rolling step, the rolled hot rolled steel sheet is cold rolled after pickling, and a cold rolled steel sheet is manufactured.
    (Continuous annealing step) [00109] In the continuous annealing step, the cold-rolled steel sheet is subjected to continuous annealing. The continuous annealing step includes a heating step for heating the cold-rolled steel sheet in a temperature range equal to or greater than "(Aci - 40) ° C and below Ac3 ° C", and a cooling step subsequently cooling the cold rolled steel blade to 660 ° C from the highest heating temperature by setting a cooling rate to 10 ° C / s or less, and a retention retention step subsequently the cold rolled steel blade in a temperature range of “450 ° C to 660 ° C” lasts 20 seconds to 10 minutes.
    (Hot stamping step) [00110] In the hot stamping step, hot stamping is performed for the steel sheet that is subjected to continuous annealing as described above after heating to a temperature equal to or greater than Ac3 and a vertical wall is formed. In addition, the vertical wall means a portion that is parallel to a press direction, or a portion that intersects with a press direction at an angle within 20 degrees. The general conditions can be used for the heating rate or the subsequent cooling rate. However, since production efficiency is extremely low at a heating rate of less than 3 ° C / s, the heating rate can be set to be equal to or more than 3 ° C / s. Additionally, since the vertical wall may not
    Petition 870180043916, of 05/24/2018, p. 42/89
    40/76 is sufficiently cooled in particular, at a cooling rate of less than 3 ° C / s, the cooling rate can be set to be equal to or more than 3 ° C / s.
    [00111] The heating method is not particularly regulated and, for example, a method for performing electric heating or a method for using a heating furnace can be employed.
    [00112] The upper limit of the highest heating temperature can be set to 1,000 ° C. In addition, maintenance at the highest heating temperature may not be performed, as it is not necessary to provide a particular retention time since the reverse transformation to the single austenite phase is obtained.
    [00113] According to the manufacturing method described above, since the steel sheet for hot press in which the hardness is uniform and which is soft is used, even in a case of hot stamping of the formed body that it has a vertical wall in which the gap with the die is easily generated, it is possible to reduce the variation in the hardness of the hot stamped body. In detail, it is possible to obtain a formed body that has a vertical wall in which, when a tempering start temperature is equal to or less than 650 ° C, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 100, when the tempering start temperature is 650 ° C to 750 ° C, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 60, and when the tempering start temperature is equal at or above 750 ° C, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 40.
    [00114] Since the steel blade is wound in a winding after the transformation from austenite to ferrite or perlite in the ROT through the hot rolling step of the second modality described above, the variation in the resistance of the steel blade accompanied
    Petition 870180043916, of 05/24/2018, p. 43/89
    41/76 with the cooling temperature deviation generated after winding is reduced. Consequently, in the continuous annealing step subsequent to the last stage of the cold rolling stage, the cold rolled steel sheet is heated in the temperature range “equal to or greater than (Aci - 40) ° C to less than Ac3 ° C ”, subsequently cooling the highest temperature to 660 ° C at a cooling rate equal to or less than 10 ° C / s, and subsequently maintaining it in the temperature range of“ 450 ° C to 660 ° C ”For 20 seconds to 10 minutes, it is possible to check the uniformity of the microstructure in the same way as or an improved way to the method to manufacture a steel blade described in the first modality.
    [00115] In the continuous annealing line, a hot dip galvanizing process, a galvanizing and annealing process, a cast aluminum electrodeposition process, a cast aluminum alloy electrodeposition process, and a electroplating process can also be carried out. The effects of the present invention are not lost even when the electroplating process is carried out after the annealing step.
    [00116] As shown in the schematic view of Figure 2, the microstructure of the steel sheet submitted to the cold rolling step is a non-recrystallized ferrite. In the method of manufacturing a hot stamped body that has a vertical wall according to the second modality, in addition to the first modality in which, in the continuous annealing step, heating to a heating range “equal to or greater than ( Ac1 - 40) ° C and below Ac 3 ° C ”, the heating carried out until it has a double phase coexistence with the austenite phase in which the non-recrystallized ferrite remains slightly, it is possible to decrease the heating temperature for the continuation uniform recovery and recrystallization of the ferrite in the winding, even with
    Petition 870180043916, of 05/24/2018, p. 44/89
    42/76 the heating temperature from Άοι'Ό to (Ac 1 - 40) ° C where the reverse transformation of austenite does not occur. Additionally, through the use of the hot-rolled blade that shows the uniform structure, after heating to a temperature equal to or greater than Ac1 ° C and less than Ac3 ° C, it is possible to decrease the temperature and shorten the maintenance time after cooling at a cooling rate equal to or less than 10 ° C / s, compared to the first mode. This shows that the transformation of ferrite proceeds faster in the cooling stage of austenite through obtaining the uniform microstructure, and it is possible to achieve sufficiently the uniformity and softness of the structure, even with the conditions of maintaining the lower temperature and the short time. That is, in the maintenance step of maintaining the steel blade in the temperature range of “450 ° C to 660 ° C” for 20 seconds to 10 minutes, the thickening of C in the untransformed austenite occurs at the same time as the transformation Ferrite and precipitation of cementite or transformation of perlite occur quickly by retaining it in the same temperature range. [00117] From these points of view, when the temperature is less than (Ac1 - 40) ° C, since the recovery and recrystallization of the ferrite are insufficient, it is established as the lower limit, and meanwhile, when the temperature is equal to or greater than Ac3 ° C, since the transformation of ferrite does not occur sufficiently and the resistance after annealing increases significantly through the delay of generation of ferrite nucleation through the B addition effect, it is established as the threshold higher. In addition, in the subsequent cooling step at a cooling rate equal to or less than 10 ° C / s and the maintenance maintenance step in a temperature range of “450 ° C to 660 ° C” for 20 seconds to 10 minutes, the softening is provided by the growth of the ferrite by nucleation of the remaining ferrite.
    Petition 870180043916, of 05/24/2018, p. 45/89
    43/76 [00118] In this document, in the maintenance step of maintaining the steel blade in a temperature range of “450 ° C to 660 ° C” for 20 seconds to 10 minutes, the precipitation of cementite or the transformation of perlite can be promoted in the unprocessed austenite in which C is thickened after the transformation of ferrite. Therefore, according to the method to manufacture a formed body that has a vertical wall according to the modality, even in a case of heating a material that has high hardenability to a temperature just below the point of Ac3 by continuous annealing, the most parts of the microstructure of the steel blade can be established as ferrite and cementite. According to the state of further processing, bainite, martensite, and the remaining austenite exist slightly after cooling, in some cases. [00119] Additionally, if the temperature in the maintenance step exceeds 660 ° C, the ferrite transformation procedure is delayed and the annealing takes a long time. On the other hand, when the temperature is lower than 450 ° C, the ferrite that is generated by the transformation is hardened, it is difficult for the precipitation of cementite or for the transformation of perlite to proceed or to bainite or martensite, which are products lower temperature transformation occurs. Additionally, when the maintenance time exceeds 10 minutes, the continuous annealing installation subsequently becomes longer and more expensive and on the other hand, when the maintenance time is less than 20 seconds, the transformation of ferrite, the precipitation of cementite or transformation of perlite is insufficient, the structure is formed mainly of bainite or martensite in which most parts of the microstructure after cooling are in the hardened phase and the steel blade is hardened.
    [00120] Figures 3A to 3C show variation in steel blade resistance for hot stamping after continuous annealing
    Petition 870180043916, of 05/24/2018, p. 46/89
    44/76 with different winding temperatures for hot rolled winding. Figure 3A shows a case of carrying out continuous annealing by setting a winding temperature to 680 ° C, Figure 3B shows a case of carrying out continuous annealing by setting a winding temperature to 750 ° C, that is, at temperature range “700 ° C to 900 ° C” (range of ferrite transformation and perlite transformation) and Figure 3C shows a case of continuous annealing by establishing a winding temperature at 500 ° C, ie , in the temperature range of “25 ° C to 500 ° C” (range of transformation of bainite and transformation of martensite). In Figures 3A to 3C, ATS indicates the variation of the steel blade (maximum limit value for tensile strength of steel blade - minimum value thereof). As clearly shown in Figures 3A to 3C, through continuous annealing with suitable conditions, it is possible to obtain uniform and smooth hardness of the steel blade after annealing.
    [00121] Through the use of steel that has uniform hardness, in the hot stamping step, even in a case of manufacture of the formed body that has the vertical wall where the cooling rate easily becomes slower than in other parts , it is possible to stabilize the hardness of a body component formed after hot stamping. In addition, for the portion that is an electrode that retains the portion in which a temperature does not rise by electric heating and in which the material hardness of the steel blade itself affects the product hardness, by uniformly organizing the hardness of the product. material of the steel blade itself, it is possible to improve the accuracy of the product quality organization of the body formed after hot stamping.
    [00122] Above, the present invention has been described based on priPetition 870180043916, of 05/24/2018, p. 47/89
    45/76 in the first modality and in the second modality, however, the present invention is not limited only to the modalities described above and several modifications within the scope of the claims can be made. For example, even in the hot rolling step or in the continuous annealing step of the first modality, it is possible to employ the conditions of the second modality.
    Examples [00123] In the following, Examples of the present invention will be described.
    Petition 870180043916, of 05/24/2018, p. 48/89
    Table 1
    Steel type Ç Mn Si P s N Al You B Cr Ac1 AC3 DI inch (% in large scale) (° C) (° C) - THE 0.22 1.35 0.15 0.009 0.004 0.003 0.010 0.020 0.0012 0.22 735 850 4.8 (12.9 cm) B 0.22 1.65 0.03 0.009 0.004 0.004 0.010 0.010 0.0013 0.02 725 840 3.5 (8.89 cm) Ç 0.22 1.95 0.03 0.008 0.003 0.003 0.010 0.012 0.0013 0.15 725 830 4.2 (10.66 cm) D 0.23 2.13 0.05 0.010 0.005 0.004 0.020 0.015 0.0015 0.10 720 825 5.2 (13.20 cm) AND 0.28 1.85 0.10 0.008 0.004 0.003 0.015 0.080 0.0013 0.01 725 825 3.8 (9.65 cm) F 0.24 1.63 0.85 0.009 0.004 0.003 0.032 0.020 0.0014 0.01 740 860 5.4 (13.71 cm) G 0.21 2.62 0.12 0.008 0.003 0.003 0.022 0.015 0.0012 0.10 725 820 8.0 (20.32 cm) H 0.16 1.54 0.30 0.008 0.003 0.003 0.020 0.012 0.0010 0.03 735 850 3.4 (8.63 cm) I 0.40 1.64 0.20 0.009 0.004 0.004 0.010 0.020 0.0012 0.01 730 810 4.1 (10.41 cm) J 0.21 0.82 0.13 0.007 0.003 0.003 0.021 0.020 0.0011 0.01 735 865 1.8 (4.57 cm) K 0.28 3.82 0.13 0.008 0.003 0.004 0.020 0.010 0.0012 0.13 710 770 7.1 (18.03 cm) L 0.26 1.85 1.32 0.008 0.004 0.003 0.020 0.012 0.0015 0.01 755 880 9.2 (23.36 cm) M 0.29 1.50 0.30 0.008 0.003 0.004 1,300 0.020 0.0018 0.01 735 1055 4.6 (11.68 cm) N 0.24 1.30 0.03 0.008 0.004 0.003 0.020 0.310 0.0012 0.20 730 850 4.1 (10.41 cm) O 0.22 1.80 0.04 0.009 0.005 0.003 0.010 0.020 0.0001 0.10 725 830 2.2 (5.58 cm)
    9Z / 917
    Petition 870180043916, of 05/24/2018, p. 49/89
    Steel type Ç Mn Si P s N Al You B Cr Ac1 AC3 DI inch (% in large scale) (° C) (° C) - P 0.23 1.60 0.03 0.009 0.005 0.003 0.012 0.003 0.0010 0.01 725 840 1.3 (3.30 cm) Q 0.21 1.76 0.13 0.009 0.004 0.003 0.021 0.020 0.0013 0.20 730 835 7.5 (19.05 cm) R 0.28 1.65 0.05 0.008 0.003 0.004 0.025 0.015 0.0025 0.21 725 825 7.9 (20.06 cm) s 0.23 2.06 0.01 0.008 0.003 0.003 0.015 0.015 0.0022 0.42 715 815 8.4 (21.33 cm) T 0.22 1.60 0.15 0.008 0.004 0.003 0.022 0.015 0.0021 2.35 710 810 16.1 (40.89 cm)
    47/76
    Petition 870180043916, of 05/24/2018, p. 50/89
    Table 2
    Steel type Mo Nb V Ni Ass Sn Here Mg REM (% in large scale) THE 0.05 0.003 B Ç D 0.04 0.01 0.008 0.003 AND F 0.06 0.04 0.02 0.003 G 0.2 0.005 0.003 H 0.002 I J K 0.05 L 0.002 M N 0.15 O 0.1 0.005
    9Z / 817
    Petition 870180043916, of 05/24/2018, p. 51/89
    Steel type Mo Nb V Ni Ass Sn Here Mg REM (% in large scale) P Q 0.11 R 0.15 0.08 0.002 0.003 s T
    9Z / 617
    Petition 870180043916, of 05/24/2018, p. 52/89
    Table 3
    Kind ofsteel Con-dictionn ° Hot rolling for winding conditions Continuous annealing conditions F4T F7T (AC3-80) (AC3 +40) Time from stage 4 to stage 7 Maintenance time600 ° C to Ar3 CT Temperatureheatingtaller Cooling rate Temperaturemaintenance Time tomaintenancedog [° C] [° C] [° C] [° C] [s] [s] [° C] [° C] [° C / s] [° C] [s] THE 1 955 905 770 890 2.7 2.1 680 830 3.5 585 320 2 945 900 770 890 2.9 1.3 500 825 4.2 580 330 3 945 900 770 890 2.2 0.3 800 830 4.1 585 320 4 940 900 770 890 2.8 2.5 680 700 4.3 570 330 5 945 905 770 890 2.9 3.1 675 870 4.5 580 300 6 955 910 770 890 2.5 3.2 685 820 13.5 560 290 7 950 905 770 890 2.6 2.9 680 825 5.2 530 300 8 945 905 770 890 2.2 4.6 685 810 4.6 575 45 9 880 820 770 890 4.6 8.2 580 810 4.2 560 310 10 875 810 770 890 4.5 7.9 610 710 4.3 470 35 B 1 960 890 760 880 2.2 4.0 650 820 3.5 580 290 2 950 895 760 880 2.8 1.0 500 815 5 560 300 3 945 895 760 880 2.6 3.0 670 860 4.5 560 320 4 945 900 760 880 2.9 3.0 670 810 5 500 310 5 890 830 760 880 4.8 7.2 600 805 3.9 570 50 6 900 845 760 880 5.1 7.6 590 705 4.5 460 45
    50/76
    Petition 870180043916, of 05/24/2018, p. 53/89
    Kind ofsteel Con-dictionn ° Hot rolling for winding conditions Continuous annealing conditions F4T F7T (AC3-80) (AC3 +40) Time from stage 4 to stage 7 Maintenance time600 ° C to Ar3 CT Temperatureheatingtaller Cooling rate Temperaturemaintenance Time tomaintenancedog [° C] [° C] [° C] [° C] [s] [s] [° C] [° C] [° C / s] [° C] [s] Ç 1 970 905 750 870 2.2 4.0 650 820 5.6 570 300 2 960 910 750 870 2.8 4.0 680 815 5.5 570 290 3 965 915 750 870 2.3 4.0 680 810 5.2 510 280 4 960 910 750 870 3.0 3.0 680 700 4.3 560 300 5 880 800 750 870 5.2 7.5 610 695 4.5 475 28 6 895 820 750 870 4.5 6.5 590 790 3.1 560 32 7 980 930 750 870 2.5 2.6 720 690 2.5 480 35 8 980 820 750 870 6.2 7.0 590 780 3.6 570 25 9 890 810 750 870 4.4 6.3 600 655 2.3 595 30 10 900 830 750 870 4.5 6.5 580 755 3.5 470 5
    51/76
    Petition 870180043916, of 05/24/2018, p. 54/89
    Table 4
    Kind ofsteel Condition No. Hot rolling for winding conditions Continuous annealing conditions F4T F7T (A CA-80) (A CA+40) Tempthe thestage 4to stage 7 Timeof ma-nuten-tion of600 ° C aArs CT Temperatureheating morehigh Cooling rate Maintenance temperature Maintenance time [° C] [° C] [° C] [° C] [s] [s] [° C] [° C] [° C / s] [° C] [s] D 1 950 910 745 865 3.2 4.0 680 700 2.1 500 324 2 960 910 745 865 2.1 4.0 680 810 4.3 580 320 3 965 920 745 865 2.0 4.0 680 775 1.6 580 405 4 960 915 745 865 3.3 3.0 680 775 2.9 540 270 5 965 910 745 865 2.3 4.0 680 800 2.2 540 405 6 975 930 745 865 2.9 4.0 680 800 4.3 500 270 7 960 910 745 865 2.1 1.0 500 700 2.1 680 324 8 950 920 745 865 2.1 2.0 500 775 1.6 580 405 9 950 910 745 865 2.2 0.0 750 700 2.1 550 324 10 955 915 745 865 2.3 0.0 750 775 1.6 580 405
    52/76
    Petition 870180043916, of 05/24/2018, p. 55/89
    Kind ofsteel Condition No. Hot rolling for winding conditions Continuous annealing conditions F4T F7T (AC3-80) (AC3+40) Tempthe thestage 4to stage 7 Tempthe ofmanuintentionin600 ° Cto Ar3 CT Higher heating temperature Cooling rate Maintenance temperature Maintenance time [° C] [° C] [° C] [° C] [s] [s] [° C] [° C] [° C / s] [° C] [s] AND 1 950 900 745 865 2.5 3.0 680 800 2.3 575 325 2 960 890 745 865 2.5 1.0 500 805 2.5 580 320 3 965 895 745 865 2.9 1.0 750 795 2.8 580 328 4 955 890 745 865 3.1 3.0 680 840 2.5 580 315 5 955 890 745 865 2.2 3.0 680 800 13.5 580 300 6 945 895 745 865 2.2 1.0 680 800 4.2 520 350 7 950 895 745 865 2.3 1.0 680 795 3.5 575 45 8 900 830 745 865 5.3 7.2 595 785 4.2 610 55 9 910 810 745 865 6.4 8.1 600 700 3.9 460 22 F 1 960 910 780 900 2.2 2.2 675 840 4.6 560 325 2 950 900 780 900 2.1 2.3 675 830 4.3 585 520 3 950 920 780 900 2.1 3.0 450 835 3.5 580 320 4 960 900 780 900 1.8 1.0 775 825 3.5 575 350 5 950 905 780 900 1.9 1.5 685 730 3.6 580 305
    53/76
    Petition 870180043916, of 05/24/2018, p. 56/89
    Table 5
    Kind ofsteel Condition No. Hot rolling for winding conditions Continuous annealing conditions F4T F7T (AC3-80) (AC3 + 40) Timestage 4to the stage7 Timeof ma-nuten-tion of600 ° Cto Ar3 CT Temperatureheatingment morehigh Rate ofcool-ment Temperaturemaintenancedog Maintenance time [° C] [° C] [° C] [° C] [s] [s] [° C] [° C] [° C / s] [° C] [s] G 1 960 905 740 860 2.2 2.5 680 800 3.8 555 320 2 970 910 740 860 2.5 2.6 680 805 4.2 585 545 3 950 910 740 860 2.6 2.4 400 800 4.1 575 320 4 950 915 740 860 2.3 2.2 800 790 3.5 580 315 5 955 920 740 860 2.5 2.3 680 710 3.5 580 295 H 1 960 915 770 890 2.4 2.1 685 830 4.2 580 305 2 955 920 770 890 2.5 2.5 680 760 4.1 550 310 I 1 950 905 730 850 2.6 2.1 675 800 3.2 580 290 2 955 900 730 850 2.7 2.5 670 790 2.8 540 285 J 1 945 905 785 905 2.8 2.1 680 840 3.5 580 300 2 950 910 785 905 2.6 2.1 685 750 3.8 530 310 K 1 - - 690 810 2.9 - - - - - - L 1 960 920 800 920 2.3 2.5 680 850 5.2 560 300 M 1 960 910 975 1095 2.5 4.0 680 860 4.5 580 305 N 1 - - 770 890 - - - - - - -
    54/76
    Petition 870180043916, of 05/24/2018, p. 57/89
    Kind ofsteel Condition No. Hot rolling for winding conditions Continuous annealing conditions F4T F7T (A CA-80) (Aca + 40) Timestage 4to the stage7 Timeof ma-nuten-tion of600 ° Cto Ar3 CT Temperatureheatingment morehigh Rate ofcool-ment Temperaturemaintenancedog Maintenance time [° C] [° C] [° C] [° C] [s] [s] [° C] [° C] [° C / s] [° C] [s] O 1 960 910 750 870 2.9 2.1 670 810 3.5 580 305 2 965 905 750 870 2.5 2.1 680 750 4.2 520 310 P 1 970 930 760 880 2.9 2.3 680 820 4.5 580 300 Q 1 960 910 755 875 2.1 2.5 680 810 5 575 310 R 1 940 905 745 865 2.2 2.1 610 785 4.2 575 305 s 1 945 910 735 855 2.4 2.2 605 795 3.2 585 295 T 1 - - 730 850 - - - - - - -
    55/76
    Petition 870180043916, of 05/24/2018, p. 58/89
    Table 6
    Steel type Condition No. Material Microstructure Cre / CrM Mne / MnM ATS TS_Ave Ferrite fraction Non-crystallized ferrite fraction Non-segmented perlite fractionzada [MPa] [MPa] [vol.%] [vol.%] [vol.%] - - THE 1 60 620 65 10 25 1.3 8.2 2 40 590 75 5 20 1.5 8.1 3 35 580 65 5 30 1.4 7.5 4 150 750 45 55 0 3.2 14.3 5 55 760 20 0 0 1.5 7.5 6 60 720 35 5 0 1.2 8.7 7 90 710 45 5 5 1.3 7.3 8 55 720 40 10 5 1.5 7.8 9 30 580 75 5 20 1.3 7.9 10 55 640 85 5 10 1.5 7.5 B 1 60 600 70 5 15 1.4 8.9 2 30 590 65 10 15 1.2 8.4 3 85 700 35 0 0 1.5 8.8 4 95 690 45 10 5 1.3 8.2 5 35 585 70 10 15 1.5 8.2 6 45 635 80 5 10 1.6 8.5
    56/76
    Petition 870180043916, of 05/24/2018, p. 59/89
    Steel type Condition No. Material Microstructure Cre / CrM Mne / MnM ATS TS_Ave Ferrite fraction Non-crystallized ferrite fraction Non-segmented perlite fractionzada [MPa] [MPa] [vol.%] [vol.%] [vol.%] - - Ç 1 60 610 65 10 15 1.2 7.8 2 65 605 70 15 15 1.4 8.2 3 105 705 45 10 5 1.4 8.8 4 150 685 40 60 0 3.3 12.8 5 40 645 80 10 10 2.2 9.4 6 35 620 70 5 25 1.2 8.1 7 95 730 40 60 0 3.5 11.9 8 115 725 35 10 10 1.4 8.2 9 85 820 5 95 0 2.2 9.6 10 45 735 60 15 5 1.2 7.5
    57/76
    Petition 870180043916, of 05/24/2018, p. 60/89
    Table 7
    Steel type Condition No. Material Microstructure Cre / CrM Mne / MnM ATS TS_Ave Ferrite fraction Fraction offerrite notcrystallized Non-segmented perlite fraction [MPa] [MPa] [vol.%] [vol.%] [vol.%] - - D 1 166 690 40 55 5 3.5 13.2 2 62 610 70 10 20 1.2 7.6 3 70 620 65 20 15 1.5 8.1 4 73 690 45 15 5 1.2 7.9 5 58 680 40 10 5 1.4 8.2 6 120 720 40 10 0 1.1 7.4 7 100 700 40 60 0 3.2 12.2 8 28 630 65 15 15 1.5 9.4 9 115 700 40 60 0 2.9 11.5 10 46 620 65 10 10 1.2 8.5 AND 1 80 685 75 10 15 1.5 8.6 2 60 680 70 20 10 1.2 7.8 3 55 675 65 25 10 1.1 8.2 4 80 810 40 0 0 1.5 9.1 5 80 760 30 20 0 1.3 8.8 6 90 840 45 20 5 1.4 8.5
    58/76
    Petition 870180043916, of 05/24/2018, p. 61/89
    Steel type Condition No. Material Microstructure Cre / CrM Mne / MnM ATS TS_Ave Ferrite fraction Fraction offerrite notcrystallized Non-segmented perlite fraction [MPa] [MPa] [vol.%] [vol.%] [vol.%] - - AND 7 80 950 45 15 5 1.2 7.5 8 40 630 65 10 15 1.3 8.8 9 35 610 70 30 0 2.2 9.6 F 1 70 640 65 10 15 1.5 7.6 2 50 610 60 10 20 1.2 7.8 3 45 600 70 5 15 1.3 8.2 4 40 605 75 10 15 1.5 7.5 5 135 680 45 55 0 2.5 13.5
    59/76
    Petition 870180043916, of 05/24/2018, p. 62/89
    Table 8
    Steel type Condition No. Material Microstructure Cre / CrM Mne / MnM ATS TS_Ave Ferrite fraction Fraction offerrite notcrystallized Perlite fractionnon-segmental-zada [MPa] [MPa] [vol.%] [vol.%] [vol.%] - - G 1 70 635 60 30 10 1.3 9.2 2 55 605 65 20 15 1.4 8.9 3 40 620 65 20 15 1.4 8.5 4 40 610 60 20 20 1.6 8.8 5 165 695 40 60 0 2.2 13.2 H 1 70 620 80 10 10 1.8 9.3 2 105 680 80 20 0 2.5 13.3 I 1 130 830 65 15 20 1.2 7.5 2 150 850 45 10 15 1.5 8.2 J 1 50 580 75 15 10 1.3 8.5 2 60 585 45 40 15 1.6 11.9 K 1 - - - - - - - L 1 70 650 65 25 10 1.6 9.2 M 1 140 760 70 10 20 1.7 8.5 N 1 - - - - - - - O 1 30 610 70 20 10 1.5 6.8
    60/76
    Petition 870180043916, of 05/24/2018, p. 63/89
    Steel type Condition No. Material Microstructure Cre / CrM Mne / MnM ATS TS_Ave Ferrite fraction Fraction offerrite notcrystallized Non-segmented perlite fraction [MPa] [MPa] [vol.%] [vol.%] [vol.%] - - 2 55 600 75 10 15 1.6 7.5 P 1 30 600 75 15 10 1.3 8.5 Q 1 30 595 65 20 15 1.3 8.9 R 1 65 705 60 10 30 1.8 9.2 s 1 35 605 75 10 15 1.5 9.3 T 1 - - - - - - -
    61/76
    Petition 870180043916, of 05/24/2018, p. 64/89
    Table 9
    Kind ofsteel condition n ° Type of electro-deposition Hardness variationDHvickers of the hot-stamped body when an initial tempering temperatureis 600 °: Hardness variationBody DHv vickershot stampedwhen an initial tempering temperature is 700 °: Vickers DHv hardness variation of hot stamped bodywhen a temperaturetempering initial is800 °: Coatingconversionchemistry Note ONE 1 hot dip galvanizing 55 44 28 Good 2 galvanizing and annealing 65 35 25 Good 3 hot dip galvanizing 67 38 24 Good 4 - 123 78 48 Good Remaining non-recrystallized ferrite 5 132 69 55 Good Insufficient ferrite transformation and cementite precipitation 6 144 85 63 Good Insufficient ferrite transformation 7 135 86 65 Good Insufficient ferrite transformation and cementite precipitation
    62/76
    Petition 870180043916, of 05/24/2018, p. 65/89
    Kind ofsteel condition n ° Electroplating type Hardness variationBody DHv vickershot stampedwhen an initial tempering temperatureis 600 °; Hardness variationBody DHv vickershot stampedwhen an initial tempering temperature is 700 ° C Vickers DHv hardness variation of hot stamped bodywhen a temperaturetempering initial is800 ° C Coatingconversionchemistry Note ONE 8 125 72 68 Good Insufficient ferrite transformation and cementite precipitation 9 - 65 35 22 Good 10 - 66 48 21 Good B 1 hot dip galvanizing 59 35 27 Good 2 cast aluminum electroplating plating 62 39 22 Good 3 115 74 66 Good Insufficient ferrite transformation and cementite precipitation 4 119 76 51 Good Insufficient ferrite transformation and cementite precipitation 5 galvanizing by immersion 57 44 21 Good
    63/76
    Petition 870180043916, of 05/24/2018, p. 66/89
    Kind ofsteel condition n ° Electroplating type Hardness variationDHvickers of the hot-stamped body when an initial tempering temperatureis 600 °; Hardness variationBody DHv vickershot stampedwhen an initial tempering temperature is 700 ° C Vickers DHv hardness variation of hot stamped bodywhen a temperaturetempering initial is800 ° C Coatingconversionchemistry Note hot 6 - 59 49 25 Good Ç 1 hot dip galvanizing 65 46 21 Good 2 hot dip galvanizing 67 48 25 Good 3 121 72 46 Good Insufficient ferrite transformation and cementite precipitation 4 - 126 75 48 Good Remaining non-recrystallized ferrite 5 galvanizing and annealing 67 54 19 Good 6 - 72 55 22 Good 7 hot dip galvanizing 113 75 54 Good Insufficient ferrite transformation and cementite precipitation
    9Z / 179
    Petition 870180043916, of 05/24/2018, p. 67/89
    Kind ofsteel condition n ° Electroplating type Hardness variationDHvickers of the hot-stamped body when an initial tempering temperatureis 600 ° C Hardness variationHot stamped Vickers DHv when an initial quench temperature is 700 ° C Vickers DHv hardness variation of the hot stamped body when an initial quenching temperature is800 ° C Coatingconversionchemistry Note 8 114 78 51 Good Insufficient ferrite transformation and cementite precipitation 9 135 71 55 Good Insufficient ferrite recrystallization 10 132 69 69 Good Insufficient cementite precipitation
    65/76
    Petition 870180043916, of 05/24/2018, p. 68/89
    Table 10
    Kind ofsteel condition n ° Type of ele-trodeposi-dog Vickers hardness variationDHv of the stamped body ahot when an initial tempering temperature is600 ° C Vickers DHv hardness variation of hot stamped bodywhen an initial tempering temperature is700 ° C Hardness variationBody DHv vickershot stampedwhen an initial tempering temperatureis 800 ° C Chemical conversion coating Note D 1 121 75 51 Good Non-recrystallized ferriteremaining 2 - 78 51 22 Good 3 galvanizing byhot dipping 82 52 23 Good 4 132 78 45 Good Ferrite transformationand precipitation of hundredsinsufficient tita 5 115 74 52 Good Ferrite transformationand precipitation of hundredsinsufficient tita
    66/76
    Petition 870180043916, of 05/24/2018, p. 69/89
    Kind ofsteel condition n ° Type of ele-trodeposi-dog Vickers hardness variationDHv of the stamped body ahot when an initial tempering temperature is600 ° C Vickers DHv hardness variation of hot stamped bodywhen an initial tempering temperature is700 ° C Hardness variationBody DHv vickershot stampedwhen an initial tempering temperatureis 800 ° C Chemical conversion coating Note D 6 141 81 55 Good Ferrite transformationand precipitation of hundredsinsufficient tita 7 121 64 53 Good Insufficient ferrite transformation 8 galvano-plasty 84 55 19 Good 9 128 81 49 Good Ferrite transformationand precipitation of hundredsinsufficient tita 10 - 73 44 18 Good AND 1 - 79 51 31 Good 2 galvanizing byhot dipping 77 52 25 Good 3 galvanizing byhot dipping 75 55 29 Good
    67/76
    Petition 870180043916, of 05/24/2018, p. 70/89
    Kind ofsteel condition n ° Type of ele-trodeposi-dog Vickers hardness variationDHv of the hot stamped body when an initial tempering temperature is600 ° C Vickers DHv hardness variation of the hot stamped body when an initial tempering temperature is700 ° C Hardness variationDHvickers of the hot-stamped body when an initial tempering temperatureis 800 ° C Chemical conversion coating Note AND 4 135 75 52 Good Ferrite transformationand precipitation of hundredsinsufficient tita 5 111 79 56 Good Ferrite transformationinsufficient 6 119 78 54 Good Ferrite transformationand precipitation of hundredsinsufficient tita 7 108 82 62 Good Ferrite transformationand precipitation of hundredsinsufficient tita 8 - 77 45 32 Good 9 - 76 48 31 Good
    68/76
    Petition 870180043916, of 05/24/2018, p. 71/89
    Kind ofsteel condition n ° Type of ele-trodeposi-dog Vickers hardness variationDHv of the stamped body ahot when an initial tempering temperature is600 ° C Vickers DHv hardness variation of hot stamped bodywhen an initial tempering temperature is700 ° C Hardness variationBody DHv vickershot stampedwhen an initial tempering temperatureis 800 ° C Chemical conversion coating Note F 1 in flat alloyqueam-toeletrode-position ofaluminummolten 79 54 31 Good 2 - 91 49 29 Good 3 galvanizing byimmersion inhot 89 46 28 Good 4 galvanizing byimmersion inhot 82 48 33 Good 5 132 72 55 Good Non-recrystallized ferriteremaining
    69/76
    Petition 870180043916, of 05/24/2018, p. 72/89
    Table 11
    Tlpthe ofsteel Con-dictionn Electroplating type Vickers DHv hardness variation of hot stamped bodywhen an initial tempering temperature is600 ° C Hardness variationBody DHv vickershot stampedwhen an initial tempering temperature is 700 ° C Vickers DHv hardness variation of hot stamped bodywhen an initial tempering temperature is800 ° C Coatingconversionchemistry Note G 1 - 76 51 29 Good 2 electroplating 75 52 28 Good 3 - 81 49 22 Good 4 galvanizing by immersionhot 69 44 26 5 109 71 61 Good Non-recrystallized ferriteremaining H 1 72 45 21 Good Strength after hot stamping is less than 1180 MPa 2 - 75 55 19 Good I 1 Good Cracks on the end portion generated when forming hot stamping 2 - - - - Good
    70/76
    Petition 870180043916, of 05/24/2018, p. 73/89
    Tipthe ofsteel Con-dictionn Electroplating type Vickers DHv hardness variation of the hot stamped body when an initial tempering temperature isof 600C Hardness variationHot stamped Vickers DHv when an initial quench temperature is 700 ° C Vickers DHv hardness variation of the hot stamped body when an initial quenching temperature is800 ° C Coatingconversionchemistry Note J 1 76 45 35 Good DHv is in the same rangewith the related technique method for low hardening. 2 - 77 44 34 Good K 1 - - - - Good Hot rolling is difficult L 1 91 54 32 Poor Conversion coatingpoor chemistry M 1 87 59 35 Poor Conversion coatingpoor chemistry N 1 - - - - Good Hot rolling is difficult O 1 87 54 32 Good DHv is in the same rangewith the related technique method for low hardening. 2 - 88 55 34 Good P 1 - 83 51 34 Good DHv is in the same range
    71/76
    Petition 870180043916, of 05/24/2018, p. 74/89
    Tipthe ofsteel Con-dictionn Electroplating type Vickers DHv hardness variation of hot stamped bodywhen an initial tempering temperature isof 600C Hardness variationBody DHv vickershot stampedwhen an initial tempering temperature is 700 ° C Vickers DHv hardness variation of hot stamped bodywhen an initial tempering temperature is800 ° C Coatingconversionchemistry Note with the related technique method for low hardening. Q 1 dip galvanizingthe hot 71 43 25 Good R 1 - 77 49 31 Good s 1 - 84 39 22 Good T 1 - - - - - Hot rolling is difficult
    72/76
    Petition 870180043916, of 05/24/2018, p. 75/89
    73/76 [00124] A steel that has steel material components shown in Table 1 and Table 2 was scorched and prepared, heated to 1200 ° C, laminated and wound to a CT winding temperature shown in Tables 3 to 5, being that a steel strip having a thickness of 3.2 mm is manufactured. The rolling was carried out using a hot rolling line that includes seven finishing rolling mills. Tables 3 to 5 show a “type of steel”, a “condition no.”, “Hot rolling for winding conditions”, and a “continuous annealing condition”. Aci and Ac3 were measured in an experimental way using a steel blade that has a thickness of 1.6 mm that was obtained by rolling with a cold rolling rate of 50%. For the measurement of Ac1 and Ac3, the measurement was performed from a curve of expansion and contraction by Formaster and values measured at a heating rate of 5 ° C / s are shown in Table 1. Continuous annealing was performed for the steel strip at a heating rate of 5 ° C / s with the conditions shown in Tables 3 to 5. Additionally, in Tables 6 to 8, “resistance variation (ATS)”, an “average resistance value (TS_Ave) ”, A“ microstructure of a steel strip ”,“ Cr e / CrM ”, and“ Mn e / MnM ”acquired based on the tensile strength limit measured from 10 portions of the steel strip after continuous annealing are shown. The fraction of the microstructure shown in Tables 6 to 8 was obtained by observing the cut and polished test piece with the optical microscope and measuring the ratio using a point counting method. Thereafter, electric heating with an electrode in relation to the steel sheet for hot stamping was carried out and the steel sheet for hot stamping was heated at a heating rate of 30 ° C / s so that the heating temperature highest was Ac3 ° C + 50 ° C. Then, without performing temperature maintenance after heating, the heated steel blade was hot stamped and a body formed that
    Petition 870180043916, of 05/24/2018, p. 76/89
    74/76 has a vertical wall shown in Figure 4 has been manufactured. A cooling rate of the matrix cooling was set at 20 ° C / s. The matrix used for pressing was a hat-shaped and R matrix with a type of punch and the matrix was established in 5R. Additionally, the height of the vertical hat wall was 50 mm and the maintenance pressure in white was set at 10 tones.
    [00125] Tempering was carried out by setting the initial tempering temperature at 600 ° C, 700 ° C, at 800 ° C, and the Vickers DHv hardness variation of the vertical wall of the hot stamped body is evaluated for each. For the hardness of the vertical wall, the hardness of the cross section at a position of 0.4 mm from the surface was acquired from the average of 5 values with a load of 5 kgf using a Vickers hardness tester. The evaluation results of the “Vickers DHv hardness variation of the hot stamped body when an initial quenching temperature is 600 ° C”, the “Vickers DHv hardness variation of the hot stamped body when an initial quenching temperature is 700 ° C ”and the“ Vickers DHv hardness variation of the hot stamped body when an initial tempering temperature is 800 ° C ”are shown in Tables 9 to 11.
    [00126] For the chemical conversion coating, a crystalline phosphate state was observed with five visual fields using a scanning electron microscope with magnification of 10000X by the use of weighted liquid of the type of immersion that is normally used and was determined as an approved if there was no clearance in a crystalline state (Approved: Good, Failed: Poor).
    [00127] Test Examples A-1, A-2, A-3, A-9, A-10, B-1, B-2, B-5, B6, C-1, C-2, C- 5, C-6, D-2, D-3, D-8, D-10, E-1, E-2, E-3, E-8, E-9, F-1, F-2, F-3, F-4, G-1, G-2, G-3, G-4, Q-1, R-1 and S-1 were determined to be good since they were in the range of conditions. In Test Examples A-4, C-4, D-1, D-9, F-5 and G-5, since the temperature
    Petition 870180043916, of 05/24/2018, p. 77/89
    75/76 higher heating at continuous annealing was lower than the range of the present invention, the non-recrystallized ferrite remained and DHv became higher. In Test Examples A-5, B-3, and E-4, since the highest heating temperature at continuous annealing was higher than the range of the present invention, the austenite single phase structure was obtained at higher heating and ferrite transformation and cementite precipitation in the subsequent cooling and maintenance did not proceed, the hard phase fraction after annealing became higher and DHv became higher. In Test Examples A-6 and E-5, since the cooling rate of the highest heating temperature at continuous annealing was higher than the range of the present invention, ferrite transformation did not occur sufficiently and DHv became taller. In Test Examples A-7, D-4, D-5, D-6, and E-6, since the maintenance temperature at continuous annealing was lower than the range of the present invention, the transformation of ferrite and the cementite precipitation was insufficient and DHv became higher. In Test Example D-7, since the maintenance temperature at continuous annealing was higher than the range of the present invention, the ferrite transformation did not proceed sufficiently and DHv became higher. In Test Examples A-8 and E-7, since the maintenance time at continuous annealing was shorter than the range of the present invention, the transformation of ferrite and precipitation of cementite were insufficient and DHv became higher. When comparing Test Examples B-1, C-2 and D-2 and Test Examples B4, C-3, and D-6 that have similar manufacturing conditions in the type of steel that has almost the same C concentration as the steel material and that has different DIinch values of 3.5, 4.2 and 5.2, it was found that, when the DIinch value was large, the DHv improvement was significant. Since a type of H steel had a small C proportion of 0.16%, a quenching temperature after hot stamping is
    Petition 870180043916, of 05/24/2018, p. 78/89
    76/76 made it lower and was not suitable as a hot stamped component. Since a type of steel I has a large C proportion of 0.40%, cracks on the end portion were generated at the time of hot stamping. A type of steel J had a small proportion of Mn of 0.82% and the hardenability was low. Since steel types K and N, respectively, had a large proportion of Mn of 3.82% and a proportion of Ti of 0.310%, it was difficult to perform hot rolling which is part of a manufacturing step for a hot stamped component. Since steel types L and M, respectively, had a large Si ratio of 1.32% and an Al proportion of 1,300%, the chemical conversion coating of the hot stamped component was degraded. Since a steel type O had a small proportion of B added and a steel type P had insufficient N detoxification due to the addition of Ti, the hardness was low.
    [00128] Additionally, as found in Tables 3 to 11, although the surface treatment due to electrodeposition or similar was carried out, the effects of the present invention were not disturbed.
    Industrial Applicability [00129] According to the present invention, even in the case of manufacturing a formed body that has a vertical wall from the steel sheet for hot stamping, it is possible to provide a hot stamped body that has a wall vertical that can suppress the variation in hardness of the formed body.
    Petition 870180043916, of 05/24/2018, p. 79/89
    1/5
    权利要求:
    Claims (9)
    [1]
    1. Method for manufacturing a hot stamped body, characterized by the fact that it comprises:
    hot-rolling a plate containing chemical components that include, by weight%, 0.18% to 0.35% C, 1.0% to 3.0% Mn, 0.01% to 1.0% Si, 0.001% to 0.02% P, 0.0005% to 0.01% S, 0.001% to 0.01% N, 0.01% to 1.0% Al, 0.005% to 0.2% Ti, 0.0002% to 0.005% B and 0.002% to 2.0% Cr and the balance of Fe and unavoidable impurities to obtain a hot rolled steel sheet;
    rolling the hot-rolled steel sheet that is subjected to hot rolling;
    cold rolling the hot rolled steel sheet to obtain cold rolled steel sheet;
    continuously annealing the cold rolled steel sheet which is subjected to cold rolling to obtain a hot stamping steel sheet; and perform hot stamping by heating the steel sheet for hot stamping which is continuously annealed so that a higher heating temperature is equal to or higher than Ac3 ° C and forms a vertical wall, with continuous annealing includes:
    heating the cold-rolled steel sheet to a temperature range equal to or higher than Ac1 ° C and lower than Ac3 ° C;
    cooling the cold rolled steel sheet heated from the highest heating temperature to 660 ° C at a cooling rate of 10 ° C / s or less; and retain the cooled cold-rolled steel blade over a temperature range of 550 ° C to 660 ° C for one minute to 10 minutes.
    [2]
    2. Method for manufacturing a hot stamped body, according to claim 1,
    Petition 870180043916, of 05/24/2018, p. 80/89
    2/5 characterized by the fact that the chemical components additionally include one or more from 0.002% to 2.0% of Mo, 0.002% to 2.0% of Nb, 0.002% to 2.0% of V, 0.002% to 2.0% Ni, 0.002% to 2.0% Cu, 0.002% to 2.0% Sn, 0.0005% to 0.0050% Ca, 0.0005% to 0.0050% Mg and 0.0005% to 0.0050% REM.
    [3]
    3. Method for the manufacture of a hot stamped body, according to claim 1, characterized by the fact that it also comprises carrying out any one of a hot dip galvanizing process, a galvanizing and annealing process, an electroplating process cast aluminum, a cast aluminum alloy electroplating process and an electroplating process, after continuous annealing.
    [4]
    4. Method for the manufacture of a hot stamped body, according to claim 2, characterized by the fact that it also comprises carrying out any one of a hot dip galvanizing process, a galvanizing and annealing process, an electroplating process cast aluminum, a cast aluminum alloy electroplating process and an electroplating process, after continuous annealing.
    [5]
    5. Method for manufacturing a hot stamped body, characterized by the fact that it comprises:
    hot-rolling of a plate containing chemical components that include, by weight%, 0.18% to 0.35% C, 1.0% to 3.0% Mn, 0.01% to 1.0 % Si, 0.001% to 0.02% P, 0.0005% to 0.01% S, 0.001% to 0.01% N, 0.01% to 1.0% Al, 0.005% at 0.2% Ti, 0.0002% at 0.005% B and 0.002% at 2.0% Cr and the balance of Fe and unavoidable impurities to obtain a hot-rolled steel sheet;
    rolling the hot-rolled steel sheet that is subjected to hot rolling;
    Petition 870180043916, of 05/24/2018, p. 81/89
    3/5 cold rolled hot rolled steel sheet to obtain cold rolled steel sheet;
    continuously annealing the cold rolled steel sheet which is subjected to cold rolling to obtain a hot stamping steel sheet; and perform hot stamping by heating the steel sheet for hot stamping which is continuously annealed so that a higher heating temperature is equal to or higher than Ac3 ° C and forms a vertical wall, and in the lamination hot, in the finishing hot rolling set up with a machine with 5 or more consecutive rolling chairs, rolling is carried out by establishing a FT finishing hot rolling temperature in a final Fi rolling mill in a temperature range (Ac3 - 80) ° C to (Ac 3 + 40) ° C, by establishing the time from the start of the rolling mill at a rolling mill Fi-3 which is a machine prior to the final rolling mill Fi at the end of rolling in the final rolling mill Fi to be equal to or longer than 2.5 seconds and by setting a hot rolling temperature Fi-3T in the rolling mill Fi-3 to be equal to or less is lower than FiT + 100 ° C and after retention in a temperature range of 600 ° C to Air 3 ° C for 3 seconds to 40 seconds, winding is performed, continuous annealing includes:
    heat the cold-rolled steel sheet to a temperature range equal to or higher than (Aci - 40) ° C and lower than Ac3 ° C;
    cooling the cold rolled steel sheet heated from the highest heating temperature to 660 ° C at a cooling rate of 10 ° C / s or less; and retain the cooled cold-rolled steel blade over a temperature range of 450 ° C to 660 ° C for 20 seconds to 10 minutes.
    Petition 870180043916, of 05/24/2018, p. 82/89
    4/5
    [6]
    6. Method for manufacturing a hot stamped body, according to claim 5, characterized by the fact that the chemical components additionally include one or more from 0.002% to 2.0% Mo, 0.002% to 2.0% Nb, 0.002% to 2.0% of V, 0.002% to 2.0% of Ni, 0.002% to 2.0% of Cu, 0.002% to 2.0% of Sn, 0.0005% to 0, 0050% Ca, 0.0005% to 0.0050% Mg and 0.0005% to 0.0050% REM.
    [7]
    7. Method for the manufacture of a hot stamped body, according to claim 5, characterized by the fact that it also comprises carrying out any one of a hot dip galvanizing process, a galvanizing and annealing process, an electroplating process cast aluminum, a cast aluminum alloy electrodeposition process, and electroplating process, after continuous annealing.
    [8]
    8. Method for manufacturing a hot stamped body, according to claim 6, characterized by the fact that it also comprises carrying out any one of a process of hot dip galvanizing, a process of galvanizing and annealing, an electroplating process cast aluminum, a cast aluminum alloy electrodeposition process, and electroplating process, after continuous annealing.
    [9]
    9. Hot stamped body which is formed by using the method for manufacturing a hot stamped body, as defined in any one of claims 1 to 8, characterized by the fact that when an initial tempering temperature is equal to or lower than 650 ° C, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 100, when the initial tempering temperature is 650 ° C to 750 ° C, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 60 and when the initial tempering temperature is equal to or higher
    Petition 870180043916, of 05/24/2018, p. 83/89
    5/5 than 750Ό, the Vickers DHv hardness variation of the hot stamped body is equal to or less than 40.
    Petition 870180043916, of 05/24/2018, p. 84/89
    1/6
    WS position in the width direction [mm]
    类似技术:
    公开号 | 公开日 | 专利标题
    BR112013009515B1|2018-08-07|HOT BODY MANUFACTURING METHOD WITH A VERTICAL WALL AND HOT BODY MANUFACTURING WITH A VERTICAL WALL
    US9840751B2|2017-12-12|Method for manufacturing hot stamped body and hot stamped body
    US9896736B2|2018-02-20|Method for manufacturing hot stamped body having vertical wall and hot stamped body having vertical wall
    JP5464302B2|2014-04-09|Cold-rolled steel sheet and manufacturing method thereof
    BR112012018697B1|2018-11-21|steel sheet and steel sheet production method
    BR112014002026B1|2019-03-26|HIGH RESISTANCE STEEL SHEET AND HIGH RESISTANCE GALVANIZED STEEL SHEET FOR SHAPE FIXABILITY, AND METHOD OF PRODUCTION OF THE SAME.
    BR112019010681A2|2019-09-17|high strength steel sheet
    US20170121788A1|2017-05-04|Process for manufacturing cold-rolled steel sheet
    BR112014024879B1|2019-01-22|hot-dip galvanized hot-rolled steel sheet and process to produce the same
    BR112014025955B1|2018-12-18|high strength steel plate and method to manufacture the same
    BR112014019497B1|2019-04-24|COLD LAMINATED STEEL SHEET, COATED STEEL SHEET, AND METHODS FOR PRODUCING THEM
    BRPI0520600B1|2014-11-11|"METHOD OF PRODUCTION OF A COLD LAMINATED STEEL PLATE AS WELL AS COLD LAMINATED STEEL PLATE PRODUCED BY THE METHOD".
    JP6769576B1|2020-10-14|High-strength galvanized steel sheet and its manufacturing method
    JP5454488B2|2014-03-26|High-strength cold-rolled steel sheet with excellent uniform and local deformability
    同族专利:
    公开号 | 公开日
    MX348196B|2017-06-05|
    MX361834B|2018-12-18|
    BR112013009517B1|2019-04-24|
    MX2013004357A|2013-06-24|
    US20130199676A1|2013-08-08|
    EP2631307A4|2016-11-02|
    KR20130063541A|2013-06-14|
    JPWO2012053642A1|2014-02-24|
    CA2814646A1|2012-04-26|
    EP2631308A1|2013-08-28|
    JPWO2012053637A1|2014-02-24|
    US10030280B2|2018-07-24|
    PL2631308T3|2019-05-31|
    MX2013004356A|2013-06-24|
    KR101509362B1|2015-04-07|
    CN103168106A|2013-06-19|
    WO2012053637A1|2012-04-26|
    CA2814646C|2016-03-08|
    CA2813915C|2016-03-08|
    BR112013009517A2|2016-07-26|
    KR20130055020A|2013-05-27|
    PL2631307T3|2019-09-30|
    CN103168106B|2014-11-12|
    JP5293902B2|2013-09-18|
    US20130220490A1|2013-08-29|
    US9512499B2|2016-12-06|
    ES2729056T3|2019-10-30|
    CN103261452B|2014-11-19|
    JP5224010B2|2013-07-03|
    WO2012053642A1|2012-04-26|
    EP2631307B1|2019-04-03|
    BR112013009515A2|2016-07-26|
    EP2631307A1|2013-08-28|
    CA2813915A1|2012-04-26|
    ES2711649T3|2019-05-06|
    CN103261452A|2013-08-21|
    EP2631308A4|2016-11-02|
    KR101513378B1|2015-04-17|
    EP2631308B1|2018-11-28|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JP3846206B2|2000-02-29|2006-11-15|Ｊｆｅスチール株式会社|High tensile cold-rolled steel sheet with excellent strain age hardening characteristics and method for producing the same|
    KR101094594B1|2003-09-30|2011-12-15|신닛뽄세이테쯔 카부시키카이샤|High-yield-ratio high-strength cold rolled steel sheet excelling in weldability and ductility|
    JP4448456B2|2004-01-29|2010-04-07|新日本製鐵株式会社|Case-hardened steel with excellent coarse grain prevention and fatigue characteristics during carburizing and its manufacturing method|
    JP4506476B2|2005-01-17|2010-07-21|Ｊｆｅスチール株式会社|Cold-rolled steel sheet suitable for warm forming and manufacturing method thereof|
    JP4427462B2|2005-01-21|2010-03-10|新日本製鐵株式会社|Steel member for vehicle and method for manufacturing the same|
    JP4449795B2|2005-03-22|2010-04-14|住友金属工業株式会社|Hot-rolled steel sheet for hot pressing, manufacturing method thereof, and manufacturing method of hot-press formed member|
    CN102242307B|2005-08-03|2013-03-27|住友金属工业株式会社|Hot-rolled steel sheet and cold-rolled steel sheet and manufacturing method thereof|
    DE102005051052A1|2005-10-25|2007-04-26|Sms Demag Ag|Process for the production of hot strip with multiphase structure|
    KR100711358B1|2005-12-09|2007-04-27|주식회사 포스코|High strength cold rolled steel sheet and hot dip galvanized steel sheet having excellent formability, bake hardenability and plating property, and the method for manufacturing thereof|
    JP4714574B2|2005-12-14|2011-06-29|新日本製鐵株式会社|High strength steel plate and manufacturing method thereof|
    KR100742820B1|2005-12-27|2007-07-25|주식회사 포스코|Steel wire having excellent cold heading quality and quenching property and method for producing the same|
    JP4725415B2|2006-05-23|2011-07-13|住友金属工業株式会社|Hot-pressed steel sheet, hot-pressed steel sheet member, and production method thereof|
    CN100543155C|2006-09-27|2009-09-23|马鞍山钢铁股份有限公司|The online nodularization rolling technology of a kind of medium carbon steel|
    PL2086755T3|2006-10-30|2018-05-30|Arcelormittal|Coated steel strips, methods of making the same, methods of using the same, stamping blanks prepared from the same, stamped products prepared from the same, and articles of manufacture which contain such a stamped product|
    JP5070947B2|2007-06-14|2012-11-14|住友金属工業株式会社|Hardened steel plate member, hardened steel plate and manufacturing method thereof|
    JP4995109B2|2008-02-07|2012-08-08|新日本製鐵株式会社|High-strength cold-rolled steel sheet excellent in workability and impact resistance and method for producing the same|
    KR101010971B1|2008-03-24|2011-01-26|주식회사 포스코|Steel sheet for forming having low temperature heat treatment property, method for manufacturing the same, method for manufacturing parts using the same and parts manufactured by the method|
    EP2256224B1|2008-03-27|2016-05-04|Nippon Steel & Sumitomo Metal Corporation|High-strength cold-rolled steel sheet, high-strengthgalvanized steel sheet, and high-strength alloyed hot-dip galvanized steel sheet having excellent formability andweldability, and methods for manufacturing the same|
    JP5391572B2|2008-04-08|2014-01-15|新日鐵住金株式会社|Cold rolled steel sheet, hot dip plated steel sheet, and method for producing the steel sheet|
    JP4563469B2|2008-05-16|2010-10-13|トヨタ自動車株式会社|Press processing method and press processed product|
    BRPI0915898B1|2008-07-11|2017-07-18|Nippon Steel & Sumitomo Metal Corporation|COATED ALUMINUM STEEL SHEET FOR QUICK HEATING PRESSURE HEATING METHOD, SAME PRODUCTION METHOD AND HOT STEMPING METHOD WITH QUICK HEATING USING THAT STEEL PLATE|
    JP5709151B2|2009-03-10|2015-04-30|Ｊｆｅスチール株式会社|High-strength hot-dip galvanized steel sheet with excellent formability and method for producing the same|
    JP5387073B2|2009-03-16|2014-01-15|新日鐵住金株式会社|Steel plate for hot pressing, method for manufacturing the same, and method for manufacturing steel plate member for hot pressing|
    PL2463395T3|2009-08-06|2020-04-30|Nippon Steel Corporation|Steel sheet for radiation heating, method of manufacturing the same, and steel processed product having portion with different strength and method of manufacturing the same|
    WO2011158818A1|2010-06-14|2011-12-22|新日本製鐵株式会社|Hot-stamp-molded article, process for production of steel sheet for hot stamping, and process for production of hot-stamp-molded article|
    ES2711649T3|2010-10-22|2019-05-06|Nippon Steel & Sumitomo Metal Corp|Method of manufacturing a hot stamping body having a vertical wall, and hot stamping body having a vertical wall|
    MX359051B|2010-10-22|2018-09-13|Nippon Steel & Sumitomo Metal Corp|Process for producing hot stamp molded article, and hot stamp molded article.|
    JP5752409B2|2010-12-27|2015-07-22|新日鐵住金株式会社|Manufacturing method of hot stamping molded product with small hardness variation and molded product thereof|MX359051B|2010-10-22|2018-09-13|Nippon Steel & Sumitomo Metal Corp|Process for producing hot stamp molded article, and hot stamp molded article.|
    ES2711649T3|2010-10-22|2019-05-06|Nippon Steel & Sumitomo Metal Corp|Method of manufacturing a hot stamping body having a vertical wall, and hot stamping body having a vertical wall|
    KR101108838B1|2011-06-30|2012-01-31|현대하이스코 주식회사|Quenched steel with excellent crashworthiness and method of manufacturing quenched parts using the quenched steel|
    KR101417260B1|2012-04-10|2014-07-08|주식회사 포스코|High carbon rolled steel sheet having excellent uniformity and mehtod for production thereof|
    BR112015004191B1|2012-08-28|2020-03-24|Nippon Steel Corporation|STEEL SHEET|
    CN103331390B|2013-07-10|2015-03-11|鞍钢股份有限公司|Manufacturing method of automotive U-shaped beam|
    CN103469090A|2013-09-17|2013-12-25|北京科技大学|Annealing method of ultrahigh-strength hot-forming steel|
    EP2851440A1|2013-09-19|2015-03-25|Tata Steel IJmuiden BV|Steel for hot forming|
    EP2988887A2|2013-09-19|2016-03-02|Tata Steel IJmuiden BV|Steel for hot forming|
    JP6062353B2|2013-12-12|2017-01-18|株式会社神戸製鋼所|Steel sheet for hot press|
    KR101568549B1|2013-12-25|2015-11-11|주식회사 포스코|Steel sheet for hot press formed product having high bendability and ultra high strength, hot press formed product using the same and method for manufacturing the same|
    CA2935638C|2014-01-06|2019-08-27|Nippon Steel & Sumitomo Metal Corporation|Hot-formed member and method of manufacturing same|
    KR101612367B1|2014-02-17|2016-04-14|현대자동차주식회사|Non-normalized steel composition with improved material properties and the connecting rod using the same and method for manufacturing the connecting rod|
    CN106715745A|2014-03-28|2017-05-24|塔塔钢铁艾默伊登有限责任公司|Method for hot forming a coated steel blank|
    CN106460115B|2014-05-29|2019-03-12|新日铁住金株式会社|It is heat-treated steel and its manufacturing method|
    KR101934176B1|2014-06-13|2018-12-31|신닛테츠스미킨 카부시키카이샤|Steel material for cold forging|
    CN104087862A|2014-07-10|2014-10-08|太原重工股份有限公司|Alloy composition, semi-autogenous mill lining plate and manufacturing method of lining plate|
    CN105506509B|2014-09-26|2017-07-21|鞍钢股份有限公司|A kind of high intensity aludip and its manufacture method|
    JP6179674B2|2014-10-30|2017-08-16|Ｊｆｅスチール株式会社|High-strength steel sheet, high-strength hot-dip galvanized steel sheet, high-strength hot-dip aluminum-plated steel sheet, high-strength electrogalvanized steel sheet, and methods for producing them|
    DE102014017274A1|2014-11-18|2016-05-19|Salzgitter Flachstahl Gmbh|Highest strength air hardening multiphase steel with excellent processing properties and method of making a strip from this steel|
    WO2016148045A1|2015-03-18|2016-09-22|株式会社神戸製鋼所|Steel sheet for hot pressing and method for producing same|
    JP6082451B2|2015-03-18|2017-02-15|株式会社神戸製鋼所|Steel sheet for hot pressing and manufacturing method thereof|
    KR102000863B1|2015-03-31|2019-07-16|닛폰세이테츠 가부시키가이샤|METHOD FOR PRODUCING THE SAME, AND HOT STAMP FORMED PRODUCT|
    JP6075517B1|2015-04-01|2017-02-08|Ｊｆｅスチール株式会社|Hot-rolled steel sheet and manufacturing method thereof|
    TWI605133B|2015-05-26|2017-11-11|Nippon Steel & Sumitomo Metal Corp|Steel plate and its manufacturing method|
    CN105018687A|2015-06-26|2015-11-04|江苏宏宇模具集团有限公司|Hot-work die steel protection device|
    RU2605034C1|2015-11-20|2016-12-20|Федеральное Государственное Унитарное Предприятие "Центральный научно-исследовательский институт черной металлургии им. И.П. Бардина" |Hot-rolled steel for hot forming|
    DE102016100648B4|2015-12-23|2018-04-12|Benteler Automobiltechnik Gmbh|A heat treatment furnace and method for heat treating a precoated sheet steel plate and method of making a motor vehicle component|
    US10619223B2|2016-04-28|2020-04-14|GM Global Technology Operations LLC|Zinc-coated hot formed steel component with tailored property|
    US10385415B2|2016-04-28|2019-08-20|GM Global Technology Operations LLC|Zinc-coated hot formed high strength steel part with through-thickness gradient microstructure|
    US10288159B2|2016-05-13|2019-05-14|GM Global Technology Operations LLC|Integrated clutch systems for torque converters of vehicle powertrains|
    US10240224B2|2016-08-12|2019-03-26|GM Global Technology Operations LLC|Steel alloy with tailored hardenability|
    CN106811681B|2017-01-17|2018-03-30|北京科技大学|A kind of preparation method of no B hot formings steel|
    US10260121B2|2017-02-07|2019-04-16|GM Global Technology Operations LLC|Increasing steel impact toughness|
    JP6617836B2|2017-02-20|2019-12-11|日本製鉄株式会社|Hot stamping body|
    KR102010048B1|2017-06-01|2019-10-21|주식회사 포스코|Steel sheet for hot press formed member having excellent paint adhesion and corrosion resistance after painted and method for manufacturing thereof|
    KR102021200B1|2017-06-27|2019-09-11|현대제철 주식회사|Hot stamping product and method of manufacturing the same|
    WO2019004540A1|2017-06-27|2019-01-03|현대제철 주식회사|Hot-stamped part and method for manufacturing same|
    CN109280861A|2017-07-21|2019-01-29|蒂森克虏伯钢铁欧洲股份公司|Flat product and its production method with good resistance to aging|
    JP6493472B2|2017-09-05|2019-04-03|新日鐵住金株式会社|Manufacturing method of hot press-formed member|
    CN111197145B|2018-11-16|2021-12-28|通用汽车环球科技运作有限责任公司|Steel alloy workpiece and method for producing a press-hardened steel alloy part|
    WO2021123886A1|2019-12-19|2021-06-24|Arcelormittal|High toughness hot rolled and annealed steel sheet and method of manufacturing the same|
    WO2021254610A1|2020-06-17|2021-12-23|Thyssenkrupp Steel Europe Ag|Method for producing a sheet steel product, sheet steel product, and use of such a sheet steel product|
    WO2022050501A1|2020-09-01|2022-03-10|현대제철 주식회사|Material for hot stamping and method for manufacturing same|
    CN112195410B|2020-09-30|2022-02-18|首钢集团有限公司|Steel for automobile stamping part, preparation method of steel and automobile stamping part|
    法律状态:
    2018-02-27| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|
    2018-06-05| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2018-08-07| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|
    2019-11-26| B25D| Requested change of name of applicant approved|Owner name: NIPPON STEEL CORPORATION (JP) |
    2021-08-17| B21F| Lapse acc. art. 78, item iv - on non-payment of the annual fees in time|Free format text: REFERENTE A 10A ANUIDADE. |
    2021-12-07| B24J| Lapse because of non-payment of annual fees (definitively: art 78 iv lpi, resolution 113/2013 art. 12)|Free format text: EM VIRTUDE DA EXTINCAO PUBLICADA NA RPI 2641 DE 17-08-2021 E CONSIDERANDO AUSENCIA DE MANIFESTACAO DENTRO DOS PRAZOS LEGAIS, INFORMO QUE CABE SER MANTIDA A EXTINCAO DA PATENTE E SEUS CERTIFICADOS, CONFORME O DISPOSTO NO ARTIGO 12, DA RESOLUCAO 113/2013. |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2010-237249|2010-10-22|
    JP2010237249|2010-10-22|
    PCT/JP2011/074320|WO2012053642A1|2010-10-22|2011-10-21|Method for manufacturing hot stamped body having vertical wall, and hot stamped body having vertical wall|
    [返回顶部]