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    • 专利摘要:
    Patent Summary: "Hot-stamped steel and method for producing hot-stamped steel". The invention relates to a hot-stamped steel which satisfies an expression of (5 x [si] + [mn]) / [c]> 11 when [c] represents an amount of c by mass%, [ si] represents an amount of si by mass%, and [mn] represents an amount of mn by mass%, a metallographic structure after hot stamping includes 40% to 90% of a ferrite, and 10% to 60% of a ferrite. a martensite in an area fraction, a total of a ferrite area fraction, and a martensite area fraction is 60% or more, a martensite hardness measured with a nanoendent meets a h2 / h1 <1.10 and shm <20, and ts x? which is a product of a tensile strength ts and a hole expansion ratio ?, is 50000 mpa-%, or more.
    公开号:BR112014017100B1
    申请号:R112014017100-9
    申请日:2013-01-11
    公开日:2019-04-24
    发明作者:Toshiki Nonaka；Satoshi Kato；Kaoru Kawasaki；Toshimasa Tomokiyo
    申请人:Nippon Steel & Sumitomo Metal Corporation；
    IPC主号:
    专利说明:

    Descriptive Report of the Invention Patent for HOT STAMPING STEEL AND METHOD FOR PRODUCTION OF HOT STAMPING STEEL.
    Technical Field of the Invention [001] The present invention relates to a hot stamped steel for which a cold rolled steel sheet for hot stamping having an excellent formability after hot stamping is used, and a method for producing the same .
    [002] Priority is claimed in Japanese Patent Application No. 2012-004550, filed on January 13, 2012, the content of which is incorporated herein by reference.
    Related technique [003] At the moment, a steel plate for a vehicle is required to be improved in terms of collision safety and to have a reduced weight. In such a situation, hot stamping (also called hot pressing, hot stamping, die galvanizing, pressing galvanizing, or the like) is drawing attention as a method for obtaining high strength. Hot stamping refers to a forming method in which a steel sheet is heated to a high temperature of, for example, 700 ° C or more, then hot formed in order to improve the formability of the steel sheet , and quenched by cooling after formation, thus obtaining the desired qualities of the material. As described above, a steel plate used for a vehicle body structure is required to have high pressability and high strength operability. A steel plate having a ferrite and martensite structure, a steel plate having a ferrite and bainite structure, a steel plate containing residual austenite in a structure or the like, are known as a steel plate having both pressing and operability high resistance. In between
    Petition 870180160940, of 12/10/2018, p. 10/66
    2/47 these steel sheets, a multiphase steel sheet having martensite dispersed on a ferrite base have a low yield ratio and a high tensile strength, and in addition, it has excellent elongation characteristics. However, the multiphase steel sheet has poor hole expandability, as it concentrates stress at the interface between ferrite and martensite, and fracture is likely to start from the interface.
    [004] For example, Patent Documents 1 to 3 disclose the multiphase steel sheet. In addition, Patent Documents 4 to 6 describe the relationships between the hardness and formability of a steel sheet.
    [005] However, even with these techniques of the related technique, it is difficult to obtain a steel plate that satisfies the current requirements for a vehicle, such as an additional weight reduction, and more complicated shapes of the components.
    Prior Art Documents Patent Document [Patent Document 1] Japanese Unexamined Patent Application, First Publication No. H6-128688 [Patent Document 2] Japanese Unexamined Patent Application, First Publication No. 2000-319756 [ Patent Document 3] Japanese Unexamined Patent Application, First Publication No. 2005-120436 [Patent Document 4] Japanese Unexamined Patent Application, First Publication No. 2005-256141 [Patent Document 5] Patent Application Japanese Unexamined, First Publication No. 2001-355044 [Patent Document 6] Japanese Unexamined Patent Application, First Publication No. HI 1-189842 Disclosure of Invention
    Problems to be solved by the invention
    Petition 870180160940, of 12/10/2018, p. 11/66
    3/47 [006] An objective of the present invention is to provide a hot-stamped steel, for which a cold-rolled steel sheet capable of ensuring strength and having a more favorable hole expandability when produced from hot-stamped steel, is used, and a method for producing the same hot stamped steel.
    Means to Solve the Problem [007] The present inventors carried out intensive studies related to a cold rolled steel plate for hot stamping that ensures a resistance after hot stamping (after quenching in a hot stamping process), and has a excellent formability (hole expandability). As a result, it was found that, with respect to the composition of the steel, when an appropriate relationship is established between the amounts of Si, the amount of Mn and the amount of C, a fraction of ferrite and a fraction of a martensite on the plate steel are adjusted to predetermined fractions, and the hardness ratio (difference of a hardness) of the martensite between a surface part of a sheet thickness and a central part of the sheet thickness of the steel sheet and the hardness distribution of the martensite in the central part of the sheet thickness are adjusted in specific ranges, it is possible to industrially produce a cold rolled steel sheet for hot stamping capable of ensuring, on the steel sheet, a formability, that is, a characteristic of TS x λ> 50000 MPa-%, which is a higher value than ever in terms of TS x λ which is a product of TS tensile strength and a bore expansion ratio λ. Furthermore, it has been found that when this cold rolled steel sheet is used for hot stamping, a hot stamped steel having excellent formability even after hot stamping is obtained. In addition, it was also made clear that the suppression of segregation of
    Petition 870180160940, of 12/10/2018, p. 12/66
    4/47
    MnS in the central part of the plate thickness of the cold rolled steel plate for hot stamping is also effective in improving the formability (bore expandability) of hot stamped steel. In addition, it was also verified that, in cold rolling, an adjustment of a fraction of a reduction of cold rolling to a reduction of total cold rolling (reduction of cumulative rolling) of a support more superior to a third support based on more superior support within a specific range, it is effective in controlling a martensite hardness. In addition, the inventors have found a variety of aspects of the present invention, as described below. In addition, it was found that the effects are not impaired even when a hot dip galvanized layer, a galvanized layer, an electro-galvanized layer, and an aluminized layer are formed on the cold-rolled steel sheet.
    (1) That is, according to a first aspect of the present invention, a hot stamped steel includes, by weight%, C: 0.030% to 0.150%, Si: 0.010% to 1.00%, Mn: 1, 50% to 2.70%, P: 0.001% to 0.060%, S: 0.001% to 0.010%, N: 0.0005% to 0.0100%, Al: 0.010% to 0.050%, and, optionally, one or more than B: 0.0005% to 0.0020%, Mo: 0.01% to 0.50%, Cr: 0.01% to 0.50%, V: 0.001% to 0.100%, Ti: 0.001% 0.100%, Nb: 0.001% to 0.050%, Ni: 0.01% to 1.00%, Cu: 0.01% to 1.00%, Ca: 0.0005% to 0.0050%, REM: 0.00050% to 0.0050%, and a surplus including Fe and unavoidable impurities, where, when [C] represents an amount of C per mass%, [Si] represents an amount of Si per mass%, and [Mn] represents an amount of Mn per% by mass, the following expression (A) is satisfied, a metallographic structure after hot stamping includes 40% to 90% of a ferrite, and 10% to 60% of a martensite in a fraction of area, a total of a fraction of area of the ferrite, and a fraction of area of the mart ensita is 60% or more, the metallographic structure may, option 870180160940, dated 10/12/2018, p. 13/66
    5/47 additionally include one or more than 10% or less of a perlite in a fraction of area, 5% or less of a residual austenite in a volume ratio, and less than 40% of bainite as a surplus in a fraction of area, a martensite hardness measured with a nanoendentator satisfies the following expression (B), and the following expression (C), TS x λ, which is a product of a TS tensile strength and a bore expansion ratio λ is 50000 MPa-% or more, (5x [Si] + [Mn]) / [C]> 11 (A),
    H2 / H1 <1.10 (B), aHM <20 (C), and H1 is an average hardness of martensite on a surface part of a sheet thickness after hot stamping, H2 is an average hardness of martensite in a central part of the sheet thickness which is an area having a width of 200 pm in one direction of the thickness in a center of the sheet thickness after hot stamping, and aHM is a variation of the average hardness of the martensite in the part plate thickness after hot stamping.
    [008] (2) In hot stamped steel, according to the above (1), a fraction of the MnS area existing in hot stamped steel, and having an equivalent circle diameter of 0.1 pm to 10 pm can be 0.01% or less, and the following expression (D) can be satisfied, n2 / n1 <1.5 (D), and n1 is an average number density per 10,000 pm 2 of the MnS having the circle diameter equivalent from 0.1 pm to 10 pm in a 1/4 part of the sheet thickness after hot stamping, and n2 is an average number density per 10,000 pm 2 of MnS having the equivalent circle diameter of 0, 1 pm to 10 pm in the central part of the thickPetition 870180160940, from 10/12/2018, p. 14/66
    6/47 sheet metal after hot stamping.
    [009] (3) In hot stamped steel, according to the above (1) or (2), a hot dip galvanization can be formed on a surface of the same.
    [0010] (4) In hot stamped steel, according to the above (3), a galvanizing can be formed on a surface of hot dip galvanizing.
    [0011] (5) In hot stamped steel, according to the above (1) or (2), an electroplating can be formed on a surface of the same.
    [0012] (6) In hot stamped steel, according to the above (1) or (2), an aluminization can be formed on a surface of the same.
    [0013] (7) In accordance with another aspect of the present invention, there is provided a method for producing a hot stamped steel including subjecting the steel to continuous casting having a chemical composition according to the above (1), and obtaining a steel, heating of steel, hot rolling of steel with a hot rolling installation including a plurality of supports, winding of steel after hot rolling, stripping of steel after winding, cold rolling of steel with an installation of cold rolling including a plurality of supports after blasting under a condition that meets the following expression (E), annealing in which the steel is annealed below 700 ° C to 850 ° C and cooled after cold rolling, hardening lamination of the steel after being cooled and then annealed, and hot stamping in which the steel is heated to a temperature range of 700 ° C to 1000 ° C after hardening lamination, stamped here uent within the temperature range, and then cooled to room temperature or more, and 300 ° C or less,
    Petition 870180160940, of 12/10/2018, p. 15/66
    7/47
    1.5 x r1 / r + 1.2 x r2 / r + r3 / r> 1.0 (E), and the ri (i = 1, 2, 3) represents an individual target cold rolling reduction in one i-th support (i = 1, 2, 3) based on a more superior support in the plurality of supports in cold rolling in unit%, and r represents a reduction of total cold rolling in cold rolling in unit%.
    [0014] (8) In the method for producing hot stamped steel, according to the above (7), when CT represents a winding temperature in the winding unit of ° C, [C] represents the amount of C by% by mass, [Mn] represents the amount of Mn per% by mass, [Si] represents the amount of Si by% by mass, and [Mo] represents the amount of Mo by% by mass in the steel plate, the following expression (F) can be satisfied,
    560 - 474 x [C] - 90 x [Mn] - 20 x [Cr] - 20 x [Mo] <CT <830 - 270 x [C] - 90 x [Mn] - 70 x [Cr] - 80 x [Mo] (F).
    [0015] (9) In the method for producing hot stamped steel, according to the above (7) or (8), when T represents a heating temperature on heating in the ° C unit, t represents an internal furnace time in heating in minute unit, [Mn] represents the amount of Mn per% by mass, and [S] represents an amount of S per% by mass in the steel plate, the following expression (G) can be satisfied,
    T x ln (t) / (1.7 x [Mn] + [S])> 1500 (G).
    [0016] (10) The method for producing hot stamped steel, according to any of the above (7) to (9), may additionally include galvanizing the steel between annealing and hardening lamination.
    [0017] (11) The method for producing hot stamped steel, according to the above (10), may additionally include connecting the steel between galvanizing and hardening lamination.
    Petition 870180160940, of 12/10/2018, p. 16/66
    8/47 [0018] (12) The method for producing hot stamped steel, according to any of the above (7) to (9), may additionally include electroplating the steel after hardening lamination. [0019] (13) The method for producing hot stamped steel, according to any of the above (7) to (9), may additionally include aluminizing the steel between annealing and hardening lamination.
    Effects of the Invention [0020] According to the aspect described above of the present invention, since an appropriate relationship is established between the amount of C, the amount of Mn and the amount of Si, and, even in hot stamped steel, the the hardness of the martensite measured with a nanoendentator is adjusted to an appropriate value, it is possible to obtain a more favorable hole expandability in hot stamped steel.
    Brief Description of the Drawings [0021] Figure 1 is a graph illustrating the relationship between (5 x [Si] + [Mn]) / [C] and TS x λ on a cold rolled steel plate for hot stamping before hot stamping and hot stamped steel.
    [0022] Figure 2A is a graph illustrating the basis of an expression (B), and is a graph illustrating the relationship between an H20 / H10 and an oHM0 on cold rolled steel plate for hot stamping before hot stamping , and the relationship between H2 / H1 and OHM in hot stamped steel.
    [0023] Figure 2B is a graph illustrating the basis of an expression (C), and is a graph illustrating the relationship between oHM0 and TS x λ on cold rolled steel plate for hot stamping before hot stamping, and the relationship between OH and TS x λ in hot stamped steel.
    Petition 870180160940, of 12/10/2018, p. 17/66
    9/47 [0024] Figure 3 is a graph illustrating the relationship between n20 / n10 and TS x λ on cold rolled steel plate for hot stamping before hot stamping, and the relationship between n2 / n1 and TS x λ, in hot stamped steel, and illustrating a basis for an expression (D).
    [0025] Figure 4 is a graph illustrating the relationship between 1.5 x r1 / r + 1.2 x r2 / r + r3 / r H20 / H10 on cold rolled steel plate for hot stamping before stamping a hot, and the relationship between 1.5 xr 1 / r + 1.2 x r2 / 2 + r3 / r H2 / H1 in hot stamped steel, and illustrating a basis for an expression (E).
    [0026] Figure 5 A is a graph illustrating the relationship between an expression (F) and a fraction of a martensite.
    [0027] Figure 5B is a graph illustrating the relationship between the expression (F) and a fraction of a pearlite.
    [0028] Figure 6 is a graph illustrating the relationship between T x In (t) / (1.7 x [Mn] + [S]) and TS x λ, and illustrating a basis for an expression (G).
    [0029] Figure 7 is a perspective view of a hot stamped steel used in an example.
    [0030] Figure 8 is a flow chart illustrating a method for producing hot stamped steel for which a cold rolled steel sheet for hot stamping is used according to an embodiment of the present invention.
    Embodiments of the Invention [0031] As described above, it is important to establish an appropriate relationship between the amount of Si, the amount of Mn, and the amount of C, and provides an appropriate hardness to a martensite in a predetermined position on a steel plate in order to improve formability (hole expandability). Of this
    Petition 870180160940, of 12/10/2018, p. 18/66
    Accordingly, there are no studies related to the relationship between the formability or hardness of martensite in a hot stamped steel.
    [0032] Here, reasons for limiting a chemical composition of hot stamped steel for which a cold rolled steel sheet for hot stamping are used in accordance with an embodiment of the present invention (in some cases, also referred to as a hot stamped steel for which a cold rolled steel sheet for hot stamping is used according to the present embodiment), and steel used for producing it, will be described. Then% which is a unit of an individual component quantity indicates% by mass.
    C: 0.030% to 0.150% [0033] C is an important element to strengthen martensite and increase the strength of steel. When the amount of C is less than 0.030%, it is not possible to sufficiently increase the strength of the steel. On the other hand, when the amount of C exceeds 0.150%, the degradation of the ductility (elongation) of the steel becomes significant. Therefore, the range of the amount of C is adjusted to 0.030% to 0.150%. In a case where there is a demand for high hole expandability, the amount of C is desirably adjusted to 0.100% or less.
    Si: 0.010% to 1,000% [0034] Si is an important element for suppressing the formation of a harmful carbide, and obtaining a multiphase structure mainly including a ferrite structure and a surplus of martensite. However, in a case where the amount of Si exceeds 1.0%, the elongation or bore expandability of the steel degrades, and a chemical conversion treatment property also degrades. Therefore, the amount of Si is adjusted to 1,000% or less.
    Petition 870180160940, of 12/10/2018, p. 19/66
    11/47
    In addition, while Si is added for deoxidation, a deoxidation effect is not sufficient when the amount of Si is less than 0.010%. Therefore, the amount of Si is adjusted to 0.010% or more.
    Al: 0.010% to 0.050% [0035] Al is an important element as a deoxidizing agent. To obtain the deoxidation effect, the amount of Al is adjusted to 0.010% or more. On the other hand, even when Al is excessively added, the effect described above is saturated, and, conversely, the steel becomes brittle. Therefore, the amount of Al is adjusted in a range of 0.010% to 0.050%.
    Mn: 1.50% to 2.70% [0036] Mn is an important element to increase the durability of steel and the strengthening of steel. However, when the amount of Mn is less than 1.50%, it is not possible to sufficiently increase the strength of the steel. On the other hand, when the amount of Mn exceeds 2.70%, since the durability increases more than necessary, an increase in the strength of the steel is caused, and, consequently, the elongation or bore expansion of the steel degrades. Therefore, the amount of Mn is adjusted in a range of 1.50% to 2.70%. In a case where there is a demand for high elongation, the amount of Mn is desirably adjusted to 2.00% or less. P: 0.001% to 0.060% [0037] In a case where the quantity is large, P segregates to a grain limit, and deteriorates the local ductility and weldability of the steel. Therefore, the amount of P is adjusted to 0.060% or less. On the other hand, since an unnecessary increase in P leads to an increase in the refining cost, the amount of P is desirably adjusted to 0.001% or more.
    S: 0.001% to 0.010%
    Petition 870180160940, of 12/10/2018, p. 20/66
    12/47 [0038] S is an element that forms MnS and significantly deteriorates local ductility or weldability. Therefore, the upper limit on the amount of S is set to 0.010%. In addition, in order to reduce refining costs, a lower limit on the amount of S is desirably adjusted to 0.001%.
    N: 0.0005% to 0.0100% [0039] N is an important element to precipitate AlN and the like, and to miniaturize crystal grains. However, when the amount of N exceeds 0.0100%, a solid solution of N (solid nitrogen solution) remains, and the ductility of the steel is degraded. Therefore, the amount of N is adjusted to 0.0100% or less. Due to a refining cost problem, the lower limit on the amount of N is desirably adjusted to 0.0005%.
    [0040] The hot stamped steel for which the cold rolled steel sheet for hot stamping is used, according to the embodiment, has a basic composition including the components described above, Fe as a surplus, and unavoidable impurities, but it may additionally contain any one or more elements of Nb, Ti, V, Mo, Cr, Ca, REM (rare earth metal), Cu, Ni and B as elements that have thus been used in amounts that are equal to or smaller than the upper limits described above, to improve strength, to control a form of a sulfite or an oxide, and the like. Since chemical elements are not necessarily added to the steel sheet, the lower limits of these are 0%. [0041] Nb, Ti and V are elements that precipitate a fine carbonitride and strengthen the steel. In addition, Mo and Cr are elements that increase durability and strengthen steel. To obtain these effects, it is desirable to contain Nb: 0.001% or more, Ti: 0.001% or more, V: 0.001% or more, Mo: 0.01% or more, and Cr: 0.01% or more.
    [0042] However, even when Nb: more than 0.050%, Ti: more
    Petition 870180160940, of 12/10/2018, p. 21/66
    13/47 than 0.100%, V: more than 0.100%, Mo: more than 0.50%, and Cr: more than 0.50%, are contained, the strength increase effect is saturated, and there is an interest that elongation degradation or hole expandability can be caused.
    [0043] Steel can additionally contain Ca in the range of 0.0005% to 0.0050%. Ca and rare earth metal (REM) control the shape of the sulfite or oxide, and improve local ductility or bore expandability. To achieve this effect using Ca, it is preferable to add 0.0005% or more of Ca. However, since there is an interest that excessive addition can deteriorate operability, an upper limit on the amount of Ca is set to 0.0050% . For the same reason, for rare earth metal (REM) as well, it is preferable to set the lower limit of the quantity to 0.0005%, and the upper limit of the quantity to 0.0050%.
    [0044] Steel may additionally contain Cu: 0.01% to 1.00%, Ni: 0.01% to 1.00% and B: 0.0005% to 0.0020%. These elements can also improve the durability and increase the strength of the steel. However, to obtain the effect, it is preferable to contain Cu: 0.01% or more, Ni: 0.01% or more and B: 0.0005% or more. In a case where the amounts are equal to or less than the values described above, the effect that strengthens the steel is small. On the other hand, even when Cu: greater than 1.00%, Ni: greater than 1.00% and B: greater than 0.0020% are added, the effect of increasing resistance is saturated, and there is an interest that ductility can degrade.
    [0045] In a case where the steel contains B, Mo, Cr, V, Ti, Nb, Ni, Cu, Ca and REM, one or more elements are contained. The steel surplus is made up of Fe and unavoidable impurities. Elements other than the elements described above (for example, Sn, As, and the like) may additionally be contained as unavoidable impurities, considering that the elements do not impair the characteristics. Beyond
    Petition 870180160940, of 12/10/2018, p. 22/66
    In addition, when B, Mo, Cr, V, Ti, Nb, Ni, Cu, Ca and REM are contained in quantities that are less than the lower limits described above, the elements are treated as unavoidable impurities. [0046] In addition, in hot stamped steel for which the cold rolled steel sheet for hot stamping is used, according to the embodiment, as shown in figure 1, when the amount of C (mass%), the amount of Si (% by mass) and the amount of Mn (% by mass), are represented by [C], [Si] and [Mn] respectively, it is important to satisfy the following expression (A). (5x [Si] + [Mn]) / [C]> 11 (A) [0047] To satisfy a condition of TS x λ> 50000 MPa-%, the above expression (A) is preferably satisfied. When the value of (5 x [Si] + [Mn]) / [C] is 11 or less, it is not possible to obtain sufficient hole expandability. This is because, when the amount of C is large, the hardness of a hard phase becomes very high, and the difference in hardness (hardness ratio) between the hard phrase and a soft phase becomes large, and therefore , the λ value deteriorates, and when the amount of Si or the amount of Mn is small, TS becomes low. With respect to the value of (5 x [Si] + [Mn]) / [C], since the value does not change even after hot stamping, as described above, the expression is preferably satisfied during a sheet metal production.
    [0048] Generally, it is martensite rather than ferrite to dominate formability (bore expandability) in a two-phase steel (DP steel). As a result of intensive studies by the inventors regarding the martensite hardness, it was clarified that, when the difference in hardness (the hardness ratio) of the martensite between a surface part of a plate thickness and a central part of the plate thickness , and the hardness distribution of the martensite in the central part of the plate thickness, are in a predetermiPetição state 870180160940, of 10/12/2018, p. 23/66
    15/47 swimming in a phase before hot stamping (before heating to effect galvanizing in a hot stamping process), the state is almost maintained even after hot stamping, as shown in figures 2A and 2B, and the formability, such as elongation or bore expandability, becomes favorable. This is considered to be because the hardness distribution of the martensite formed before hot stamping still has a significant effect even after hot stamping, and alloy elements concentrated in the central part of the sheet thickness still maintain a state of being concentrated in the central part plate thickness even after hot stamping. That is, on the steel sheet before hot stamping, in a case where the hardness ratio between the martensite on the surface part of the sheet thickness and the martensite on the central part of the sheet thickness, is large, or a variation of martensite hardness is great, the same trend is exhibited even after hot stamping. As shown in figures 2A and 2B, the hardness ratio between the surface part of the plate thickness and the central part of the plate thickness on the cold rolled steel plate for hot stamping for hot stamped steel, according to the embodiment, before hot stamping and the hardness ratio between the surface part of the sheet thickness and the central part of the sheet thickness in hot stamped steel, for which the cold rolled steel sheet for hot stamping is used, according to the embodiment, are almost the same. In addition, similarly, the variation in the hardness of the martensite in the central part of the plate thickness in cold rolled steel plate for hot stamping for hot stamped steel, according to the embodiment, before hot stamping and the variation the hardness of the martensite in the central part of the plate thickness in hot stamped steel, for which the cold rolled steel plate for hot stamping is usedPetition 870180160940, of 10/12/2018, p. 24/66
    16/47 da, according to the embodiment, are almost the same. Therefore, the formability of cold rolled steel sheet for hot stamping for hot stamped steel, according to the embodiment, is similarly excellent for the formability of hot stamped steel for which cold rolled steel sheet for hot stamping is used, according to the embodiment.
    [0049] In addition, with respect to the martensite hardness measured with a nanoendentator produced by Hysitron Corporation at 1000 times magnification, the inventors found that the following expression (B) and the following expression (C) ((H) and ( I) also) being satisfied are advantageous to the formability of hot stamped steel. Here, H1 is the average hardness of the martensite on the surface part of the sheet thickness which is within an area having a width of 200 pm in one direction of the thickness of an outermost layer of the steel sheet in the direction of the thickness in the stamped steel hot, H2 is the average hardness of martensite in an area having a width of ± 100 pm in the direction of thickness from the central part of the plate thickness to the central part of the plate thickness in hot stamped steel, and σΗΜ is the variation of martensite hardness in an area having a width of ± 100 pm in the thickness direction from the central part of the plate thickness in hot stamped steel. In addition, H10 is the hardness of the martensite on the surface part of the sheet thickness on the cold rolled steel sheet for hot stamping before hot stamping, H20 is the hardness of the martensite in the central part of the sheet thickness, ie , in an area having a width of 200 pm in the direction of the thickness in a center of the thickness of the sheet in the cold rolled steel sheet for hot stamping before the hot stamping, and 'foHM0 is the variation of the hardness of the martensite in the part central plate thickness in cold rolled steel plate for hot stamping ANPetition 870180160940, of 10/12/2018, pg. 25/66
    17/47 hot stamping. The H1, H10, H2, H20, σΗΜ and σΗΜΟ are obtained respectively from measurements of 300 points for each. An area having a width of ± 100 pm in the direction of thickness from the central part of the plate thickness refers to an area having a center in the center of the plate thickness, and having a dimension of 200 pm in the direction of the thickness.
    H2 / H1 <1.10 (B) σHM <20 (C)
    H20 / H10 <1.10 (H) σHM0 <20 (I) [0050] In addition, here, the variation is a value obtained using the following expression (K) and indicating a distribution of martensite hardness.
    [Expression 1]
    xmedium represents the average hardness value, and Xi represents a 1 th hardness. [0051] An H2 / H1 value of 1.10 or more represents that the hardness of the martensite in the central part of the plate thickness is 1.10 or more times the hardness of the martensite in the surface part of the plate thickness, and, in this case, σHM becomes 20 or more even after hot stamping, as shown in figure 2 A. When the value of H2 / H1 is 1.10 or more, the hardness of the central part of the plate thickness becomes very high, TS x λ becomes less than 50000 MPa-%, as shown in figure 2B, and sufficient formability cannot be achieved both before galvanizing (ie before hot stamping) and after galvanizing (this is, after hot stamping). In addition, theoretically, there is a case where the lower limit of H2 / H1 becomes the same in the central part of the plate thickness and in the surface part of the plate thickness unless
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    18/47 a special treatment is carried out; however, in a current production process, when considering productivity, the lower limit is, for example, up to approximately 1.005. What was described above with respect to the H2 / H1 value should also apply in a similar way to the H20 / H10 value.
    [0052] In addition, the variation of oHM being 20 or more even after hot stamping indicates that a diffusion of martensite hardness is large, and parts where the hardness is very high locally exist. In this case, TS x λ becomes less than 50,000 MPa%, as shown in figure 2B, and sufficient formability of the hot stamped steel cannot be achieved. What has been described above with respect to the oHM value should also apply in a similar way to the oHM0 value.
    [0053] In hot stamped steel, according to the embodiment, the fraction of ferrite area in a metallographic structure after hot stamping is 40% to 90%. When the ferrite area fraction is less than 40%, sufficient elongation, or sufficient bore expandability, cannot be achieved. On the other hand, when the ferrite area fraction exceeds 90%, the martensite becomes insufficient, and sufficient strength cannot be achieved. Therefore, the area fraction of ferrite in hot stamped steel is adjusted to 40% to 90%. In addition, the metallographic structure of hot stamped steel also includes martensite, a fraction of the area of the martensite is 10% to 60%, and a total fraction of the area of the ferrite and the fraction of the area of the martensite is 60% or more . All or the main parts of the metallographic structure of hot stamped steel are occupied by ferrite and martensite, and in addition, one or more of a perlite, a bainite as surplus, and a residual austenite, can be included in the metallographic structure. However, when the residual austenite remains in the metallographic structure, a fragility of operation sePetição 870180160940, of 10/12/2018, p. 27/66
    19/47 and a delayed fracture characteristic are likely to degrade. Therefore, it is preferable that the residual austenite is substantially not included; however, inevitably, 5% or less of residual austenite in a volume ratio can be included. Since perlite is a hard and fragile structure, it is preferable not to include perlite in the metallographic structure; however, inevitably, up to 10% of perlite in a fraction of an area can be included. In addition, the amount of bainite as a surplus is preferably 40% or less in a fraction of the area with respect to a region excluding ferrite and martensite. Here, the metallographic structures of ferrite, bainite as surplus, and perlite were observed through Nital pickling, and the martensite metallographic structure was observed through Le pera pickling. In both cases, a 1/4 part of the plate thickness was observed at a magnification of 1000 times. The volume ratio of the residual austenite was measured with an X-ray diffraction apparatus after polishing the steel sheet to 1/4 of the part of the sheet thickness. The 1/4 part of the plate thickness refers to a 1/4 part of the steel plate thickness away from a steel plate surface in a direction of the steel plate thickness on the steel plate.
    [0085] In the embodiment, the martensite hardness measured at 1000 times magnification is specified by the use of a nanoendentator. Since an indentation formed in an ordinary Vickers hardness test is greater than the martensite, according to the Vickers hardness test, whereas a macroscopic hardness of the martensite and its peripheral structures (ferrite and the like) can be obtained, it is not possible to obtain the hardness of the martensite itself. Since formability (hole expandability) is significantly affected by the hardness of the martensite itself, it is difficult to sufficiently assess formability with Vickers hardness alone. ConPetition 870180160940, of 12/10/2018, p. 28/66
    20/47, in the embodiment, provided that an appropriate relationship of the martensite hardness in the hot stamped steel measured with the nanoendentator is provided, it is possible to obtain an extremely favorable formability.
    [0086] In addition, on cold rolled steel plate for hot stamping before hot stamping and hot stamped steel, as a result of observing MnS at a location of 1/4 of the plate thickness and on the central to the plate thickness, it was found that it is preferable that a fraction of the MnS area having an equivalent circle diameter from 0.1 pm to 10 pm is 0.01% or less, and, as shown in figure 3, the following expression (D) ((J) too) is satisfied in order to favorably and steadily satisfy the condition of TS x λ> 50000 MPa-%. When MnS having an equivalent circle diameter of 0.1 µm or more exists during a bore expandability test, as stress is concentrated in its vicinity, fracture is likely to occur. One reason for not counting the MnS having the equivalent circle diameter of less than 0.1 pm is that an effect on the stress concentration is small. In addition, a reason for not counting the MnS having the equivalent circle diameter of more than 10 pm is that, the MnS having the grain size described above is included in the steel plate, the grain size is very small, and the steel sheet becomes unsuitable for operation. In addition, when the fraction of MnS area having the equivalent circle diameter from 0.1 pm to 10 pm exceeds 0.01%, since it becomes easy for fine fractures generated by stress concentration to propagate, the expandability of the hole further deteriorates, and there is a case where the condition of TS x 4> 50000 MPa-% is not met. Here, n1 and n10 are density of
    Petition 870180160940, of 12/10/2018, p. 29/66
    21/47 number of the MnS having the equivalent circle diameter of 0.1 pm to 10 pm in 1/4 of the part of the plate thickness in hot stamped steel and the cold rolled steel plate before hot stamping respectively, and n2 and n20 are number densities of the MnS having the equivalent circle diameter of 0.1 pm to 10 pm in the central part of the plate thickness in hot stamped steel and the cold rolled steel plate before hot stamping respectively .
    n2 / n1 <1.5 (D) n20 / n10 <1.5 (J) [0087] These relationships are all identical to steel plate before hot stamping, steel plate after hot stamping, and steel hot stamped.
    [0088] When the fraction of MnS area having the equivalent circle diameter from 0.1 pm to 10 pm is more than 0.01% after hot stamping, formability is likely to degrade. The lower limit of the fraction of the MnS area is not particularly specified; however, 0.0001% or more of MnS is present due to a measurement method described below, a limitation of magnification and a visual field, and an original amount of Mn or S.
    [0054] In addition, a value of n2 / n1 (or n20 / n10) being
    1.5 or more represents that a number density of the MnS having the equivalent circle diameter of 0.1 pm to 10 pm in the central part of the sheet thickness of the hot-stamped steel (or the cold-rolled steel sheet for stamping hot before stamping) is 1.5 or more times the number density of the MnS having the equivalent circle diameter of 0.1 pm to 10 pm in 1/4 of the sheet thickness part of the hot stamped steel (or cold rolled steel plate for hot stamping before hot stamping). In this case, formability is likely to degrade due to
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    22/47 to a segregation of the MnS in the central part of the sheet thickness of the hot-stamped steel (or the cold-rolled steel sheet for hot stamping before hot stamping). In the embodiment, the equivalent circle diameter and number density of the MnS having the equivalent circle diameter from 0.1 pm to 10 pm were measured with a field emission scanning electron microscope (Fe-SEM) manufactured by JEOL Ltd. In one measurement, a magnification was 1000 times, and a measurement area of the visual field was adjusted to 0.12 x 0.09 mm 2 (= 10800 pm 2 ~ 10000 pm 2 ). Ten visual fields were observed at 1/4 of the plate thickness part, and ten visual fields were observed at the central part of the plate thickness. The fraction of the MnS area having the equivalent circle diameter from 0.1 pm to 10 pm was computed with particle analysis software. In hot stamped steel for which the cold rolled steel sheet for hot stamping is used, according to the embodiment, the shape (shape and number) of the MnS formed before hot stamping is the same before and after stamping a hot. Figure 3 is a view illustrating a relationship between n2 / n1 and TS x λ after hot stamping, and a relationship between a n20 / n10 and TS x λ, before hot stamping, and, according to figure 3 , the n20 / n10 of the cold rolled steel sheet before hot stamping and the n2 / n1 of hot stamped steel are almost the same. This is because the shape of the MnS does not change at the heating temperature of a hot stamping, generally.
    [0055] When hot stamping is carried out on the steel sheet having the configuration described above, it is possible to achieve a tensile strength of 500 Mpa to 1500 MPa, and a significant formability improvement effect is obtained in hot stamped steel having the tensile strength of approximately 550 MPa at 1200
    Petition 870180160940, of 12/10/2018, p. 31/66
    23/47
    MPa.
    [0056] In addition, it is preferable to form a galvanizing, galvanizing, electrogalvanizing, or aluminization on a surface of hot-stamped steel for which the cold-rolled steel sheet for hot-stamping is used, according to the embodiment , in terms of rust prevention. A formation of the plating described above does not impair the effects of the embodiment. The galvanizations described above can be carried out with a well-known method.
    [0057] Hereinafter, a method for producing hot stamped steel for which cold rolled steel sheet (cold rolled steel sheet, galvanized cold rolled steel sheet, cold rolled steel sheet galvanorrecozida, an electrogalvanorrecozida cold-rolled steel plate, and an aluminized cold-rolled steel plate) for hot stamping is used, according to the embodiment, will be described.
    [0058] When producing hot-stamped steel for which the cold-rolled steel sheet for hot-stamping is used according to the embodiment, as an ordinary condition, a molten steel from a melting process in a converter is continuously melted, thereby producing a plate.
    [0059] In continuous casting, when a casting rate is fast, a precipitate of Ti and the like becomes very fine, and, when the casting rate is slow, productivity deteriorates, and, consequently, a metallographic structure of the precipitate described above thickens, and the number of particles in the metallographic structure decreases, and thus there is a case that other characteristics, such as a delayed fracture, cannot be controlled. Therefore, the casting rate is desirably 1.0 m / min at 2.5 m / min.
    [0060] The plate after casting can be laminated to
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    24/47 hot as it is. Alternatively, in a case where the plate after cooling has been cooled to below 1100 ° C, it is possible to reheat the plate after cooling to 1100 ° C to 1300 ° C in a tunnel furnace or the like, and subject the plate to lamination the hot. When a plate temperature is less than 1100 ° C, it is difficult to ensure a finishing temperature in hot rolling, which causes a degradation of the elongation. In addition, in hot stamped steel to which a hot stamping steel plate to which Ti and Nb are added is used, since a precipitate dissolution becomes insufficient during heating, which causes a decrease in resistance.
    [0061] On the other hand, when the heating temperature is higher than 1300 ° C, a generation of a scale becomes large, and there is a case in which it is not possible to make a surface property of hot stamped steel favorable. for which cold-rolled steel sheet for hot stamping is used.
    [0062] In addition, to decrease the fraction of area of MnS having the equivalent circle diameter from 0.1 pm to 10 pm, when the amount of Mn and the amount of S in the steel are respectively represented by [Mn] and [ S] per mass%, it is preferable for a temperature T (° C) of a furnace heating prior to hot rolling, an internal furnace time t (minutes), [Mn] and [S] satisfy the following expression (G) as shown in figure 6.
    T x In (t) / (1.7 x [Mn] + [S])> 1500 (G) [0063] When T x In (t) / (1.7 x [Mn] + [S]) is equal to or less than 1500, the fraction of the MnS area having the equivalent circle diameter from 0.1 pm to 10 pm becomes large, and there is a case where a difference between the number density of the MnS having the equivalent circle diameter from 0.1 pm to 10 pm in 1/4 of the part of the plate thickness and the number density of the MnS having the circle diameter
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    25/47 equivalent of 0.1 pm to 10 pm in the central part of the plate thickness becomes large. The temperature of the heating furnace before hot rolling refers to an extraction temperature on one outlet side of the heating furnace, and the internal time of the furnace refers to a time elapsed from the insertion of the plate into the heating furnace. extraction of the plate from the heating furnace. Since the MnS does not change even after hot stamping as described above, it is preferable to satisfy the expression (G) in a heating process before hot rolling.
    [0064] Then, the hot rolling is carried out according to a conventional method. At this point, it is desirable to perform hot rolling on the plate at the finishing temperature (the final temperature of the hot rolling) which is set in a range of an Ar3 temperature at 970 ° C. When the finishing temperature is lower than the Ar3 temperature, the hot rolling becomes a two-phase region lamination (a + y) (ferrite + martensite two-phase region lamination), and there is an interest that stretching can degrade. On the other hand, when the finishing temperature exceeds 970 ° C, an austenite grain size thickens, and the fraction of the ferrite becomes small, and thus there is an interest that the elongation may degrade. A hot rolling facility can have a plurality of supports.
    [0065] Here, the Ar3 temperature was estimated from an inflection point of a length of a test specimen after performing a formator test.
    [0066] After hot rolling, the steel is cooled at an average cooling rate of 20 ° C / second to 500 ° C / second, and is wound at a predetermined winding temperature CT.
    [0067] In a case where the average cooling rate is lower
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    26/47 than 20 o C / second, the pearlite that causes the degradation of ductility is likely to be formed. On the other hand, an upper limit on the cooling rate is not particularly specified, and is set at approximately 500 ° C / second in consideration of a facility specification, but is not limited to this.
    [0068] After winding, pickling is carried out, and cold rolling is carried out. At this time, to obtain a strip that satisfies the expression described above (C) as illustrated in figure 4, cold rolling is performed under a condition that the following expression (E) is satisfied. When the conditions for annealing, cooling and the like described below are additionally satisfied after the rolling described above, TS x λ> 50000 MPa-% is ensured on the cold rolled steel plate for hot stamping before hot stamping and / or hot stamped steel. From the point of view of productivity, cold rolling is desirably carried out with a tandem rolling installation in which a plurality of rolling installations are linearly arranged, and the steel sheet is continuously rolled in a single direction, obtaining it if so, a predetermined thickness.
    1.5 x r1 / r + 1.2 x r2 / r + r3 / r> 1.0 (E) [0069] Here, the ri represents a reduction of individual target cold rolling (%) to an i-th support (i = 1, 2, 3) of a more superior support in cold rolling, and r represents a total target reduction of cold rolling (%) in cold rolling. The reduction of total cold rolling is a so-called cumulative reduction, and on a basis of the plate thickness at the entrance of a first support, it is a percentage of the cumulative reduction (a difference between the plate thickness at the entrance before a first passage and the plate thickness at an exit after a final passage) with respect to the base described above.
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    27/47
    When cold rolling is carried out under the conditions in which the expression (E) is satisfied, it is possible to divide the perlite sufficiently in the cold rolling even when a large perlite exists before the cold rolling. As a result, it is possible to burn the perlite or suppress the fraction of the perlite area to a minimum through annealing carried out after cold rolling, and therefore it is easy to obtain a structure in which an expression (B) and an expression (C) are satisfied. On the other hand, in a case where the expression (E) is not satisfied, the cold rolling reductions on upper chain supports are not enough, the large perlite is likely to remain, and it is not possible to form a desired martensite in the following annealing. In addition, the inventors found that, when the expression (E) is satisfied, a shape obtained from the martensite structure after annealing is kept in almost the same state even after hot stamping is carried out, and therefore the stamped steel hot for which the cold-rolled steel sheet for hot stamping is used, according to the embodiment, it becomes advantageous in terms of elongation or bore expandability even after hot stamping. In a case in which the hot stamped steel for which the cold rolled steel sheet for hot stamping is used, according to the embodiment, is heated to the two-stage region in the hot stamping, a hard phase including martensite before the hot stamping becomes an austenite structure, and the ferrite before the hot stamping remains as it is. The carbon (C) in austenite does not move to the peripheral ferrite. After that, when cooled, austenite turns into a hard phase including martensite. That is, when the expression (E) is satisfied and the H2 / H1 described above (or H20 / H10) is in a predetermined range, the H2 / H1 is maintained even after hot stamping, and the hot stamped steel becomes be excellent in terms
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    28/47 of formability.
    [00110] In the embodiment, r, r1, r2 and r3 are the reductions targeted for cold rolling. Generally, cold rolling is carried out while controlling the target reduction of cold rolling and an actual reduction of cold rolling to become substantially the same value.
    [00111] It is not preferable to perform cold rolling in a state where the actual reduction of cold rolling is unnecessarily produced to be different from the target reduction of cold rolling.
    [00112] However, in a case where there is a big difference between a reduction in target lamination and a reduction in actual lamination, it is possible to consider that the realization is carried out when the actual reduction in cold rolling satisfies the expression (E). In addition, the actual cold rolling reduction is preferably within ± 10% of the cold rolling reduction.
    [00113] After cold rolling, recrystallization is caused on the steel sheet by effect of annealing. Annealing forms a desired martensite. In addition, with respect to an annealing temperature, it is preferable to anneal by heating the steel sheet to 700 ° C to 850 ° C, and to cool the steel sheet to an ambient temperature or a temperature at which a surface treatment , such as galvanizing, is carried out. When annealing is carried out in the range described above, it is possible to stably secure a fraction of the predetermined area of the ferrite, and a fraction of the predetermined area of the martensite, to stably adjust a total of the fraction of the ferrite area, and the fraction of the area of the martensite. 60% or more, and to contribute to an improvement of TS x λ. Other annealing conditions are not particularly specified, but a retention time at 700 ° C to 850 ° C is preferably maintained for 1 second or longer, considering that productivity is not hindered in order to safely obtain a predetermined structure, and is also
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    29/47 it is preferable to properly determine a rate of temperature rise in a range of 1 ° C / second to an upper limit of a facility capacity, and to properly determine the rate of cooling in a range of 1 ° C / second to the limit superior to the facility's capacity. In a hardening lamination process, hardening lamination is carried out with a conventional method. An elongation ratio of hardening lamination is generally approximately 0.2% to 5%, and is preferable within a range where yield point elongation is avoided, and the shape of the steel sheet can be corrected.
    [00114] As an even more preferable condition of the embodiment, when the amount of C (% by mass), the amount of Mn (% by mass), the amount of Si (% by mass), and the amount of Mo (% in mass) of the steel, are represented by [C], [Mn], [Si] and [Mo], respectively, with respect to the winding temperature CT, it is preferable to satisfy the following expression (F).
    560 - 474 x [C] - 90 x [Mn] - 20 x [Cr] - 20 x [Mo] <CT <830 - 270 x [C]
    - 90 x [Mn] - 70 x [Cr] - 80 x [Mo] (F) [0070] As shown in figure 5A, when the CT winding temperature is less than 560 - 474 x [C] - 90 x [Mn] - 20 x [Cr]
    - 20 x [Mo], the martensite is excessively formed, the steel sheet becomes very hard, and there is a case where the following cold rolling becomes difficult. On the other hand, as shown in figure 5B, when the CT winding temperature exceeds 830 - 270 x [C] - 90 x [Mn] - 70 x [Cr] - 80 x [Mo], a ferrite band structure and of the perlite is likely to be formed, and in addition, a fraction of the perlite in the central part of the plate thickness is likely to increase. Therefore, a uniformity of a distribution of martensite formed in the following annealing is degraded, and it becomes difficult to satisfy the expression described above (C). In addition, there is a case where
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    30/47 it becomes difficult for the martensite to be formed in a sufficient quantity.
    [0071] When the expression (F) is satisfied, the ferrite and the hard phase have an ideal distribution form before hot stamping, as described above. In this case, when a two-phase region heating is carried out in the hot stamping, the form of distribution is maintained as described above. If the metallographic structure described above that satisfies the expression (F) can be assured more securely, the metallographic structure is maintained even after hot stamping, and hot stamped steel becomes excellent in terms of formability.
    [0072] In addition, to improve the rust prevention capacity, it is also preferable to include a galvanizing process in which a galvanization is formed between an annealing process and the hardening lamination process, and to form the galvanization on a surface of cold rolled steel sheet. In addition, it is also preferable to include an alloy process in which an alloy treatment is carried out after galvanizing. In a case where the alloy treatment is carried out, a treatment in which a galvanized surface is brought into contact with a substance that oxidizes a surface of the plate, such as water vapor, thereby thickening an oxidized film, additionally carried out on the surface.
    It is also preferable to include, for example, an electroplating process in which an electroplating is formed after the hardening lamination process, as well as electroplating and electroplating, and to form an electroplating on the surface of the cold rolled steel sheet. In addition, it is also preferable to include, instead of galvanizing, an aluminization process in which an aluminization is formed between the annealing process and the process
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    31/47 hardening lamination, and to form aluminization on the surface of cold rolled steel sheet. Aluminization is generally hot-dip aluminization, which is preferable.
    [00120] After a series of treatments described above, hot stamping is carried out by heating the steel sheet to 700 ° C to 1000 ° C. In the hot stamping process, hot stamping is desirably carried out, for example, under the following conditions. First, the steel sheet is heated to 700 ° C to 1000 ° C at a temperature rise rate of 5 ° C / second to 500 ° C / second, and hot stamping (a hot stamping process) is carried out after the retention time from 1 second to 120 seconds. To improve formability, the heating temperature is preferably an AC3 temperature or less. The AC3 temperature was estimated from the point of inflection in the length of the test specimen after performing the formastor test. Subsequently, the steel sheet is cooled, for example, to room temperature at 300 ° C at a cooling rate of 10 ° C / second to 1000 ° C / second (hot-dip galvanizing).
    [00121] When the heating temperature in the hot stamping process is less than 700 ° C, the quenching is not sufficient, and, consequently, the resistance cannot be ensured, which is not preferable. When the heating temperature is greater than 1000 ° C, the steel sheet becomes very smooth, and, in a case where a galvanization, particularly zinc galvanizing, is formed on the surface of the steel sheet, and the sheet , there is an interest that zinc can be evaporated and burned, which is not preferable. Therefore, the heating temperature in the hot stamping is preferably 700 ° C to 1000 ° C. When the rate of temperature increase is less than 5 ° C / second, since it is difficult to control the heating in the hot stamping, and the significant productivity petition 870180160940, from 10/12/2018, p. 40/66
    32/47 If it degrades, it is preferable to carry out heating at a rate of temperature increase of 5 ° C / second or more. On the other hand, an upper limit of the temperature rise rate of 500 ° C / second is dependent on a current heating capacity, but it is not necessary to limit it. At a cooling rate of less than 10 ° C / second, since controlling the cooling rate after the hot stamping process is difficult, and productivity also significantly degrades, it is preferable to cool the cooling rate of 10 ° C / second or more. An upper limit of the cooling rate of 1000 ° C / second depends on a current cooling capacity, but it is not necessary to limit it. One reason to set a time until hot stamping after an increase in temperature to 1 second or more is a current process control capacity (a lower limit of a facility capacity), and a reason to adjust time to stamping hot after the temperature rise at 120 seconds or less is to prevent evaporation of zinc or the like, in a case where galvanizing or the like is formed on the surface of the steel sheet. One reason to adjust the cooling temperature to room temperature at 300 ° C is to sufficiently insure the martensite and to ensure the strength of the hot stamped steel.
    [00122] Figure 8 is a flow chart illustrating the method for producing hot stamped steel for which a cold rolled steel sheet for hot stamping, according to an embodiment of the present invention, is used. The reference signals S1 to S13 in the drawing respectively correspond to the individual process described above.
    [0073] In the hot stamped steel of the embodiment, the expression (B) and the expression (C) are satisfied even after the hot stamping is carried out under the condition described above. In addition, therefore, it is possible to satisfy the condition of TS x λ,> 50000 MPa-%, even after hot stamping is carried out.
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    33/47 [0074] As described above, when the conditions described above are met, it is possible to produce hot stamped steel in which the hardness distribution or structure is maintained even after hot stamping, and, consequently, the resistance is assured and more favorable hole expandability can be achieved. Examples [0075] Steel having a composition described in Table 1 was continuously melted at a melting rate of 1.0 m / min to 2.5 m / min, a plate was heated in a heating furnace under the conditions shown in Table 2 with a conventional method as it is or after cooling the steel once, and hot rolling, was carried out at a finishing temperature of 910 ° C to 930 ° C, thus producing a hot rolled steel sheet . After that, the hot rolled steel sheet was wound at a CT winding temperature described in Table 1. After that, pickling was carried out in order to remove a scale on a surface of the steel sheet, and a sheet thickness to be produced. to be
    1.2 mm to 1.4 mm through cold rolling. At this point, cold rolling was performed so that the value of the expression (E) becomes a value described in Table 5. After cold rolling, annealing was carried out in a continuous annealing furnace at an annealing temperature described in Table 2 In one part of the steel sheets, galvanizing was additionally formed in the middle of cooling after soaking in the continuous annealing furnace, and then an alloy treatment was additionally carried out in the part of the steel sheets, thereby forming , an electroplating. In addition, an electrogalvanization or an aluminization was formed on the part of the steel sheets. In addition, hardening lamination was carried out at an elongation ratio of 1%, according to a conventional method. In this state, a sample was taken
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    34/47 to evaluate the qualities of the material and the like before hot stamping, and a quality test of the material or similar was carried out. Thereafter, to obtain a hot stamped steel having a shape as shown in figure 7, the hot stamping in which a temperature was increased at a rate of temperature rise from 10 ° C / second to 100 ° C / second, at steel plate was kept at a heating temperature of 780 ° C for 10 seconds, and was cooled to a cooling rate of 100 ° C / second to 200 ° C or less, was carried out. A sample was cut from a location in figure 7 on a hot stamped steel obtained, the material quality test and the like were performed, and the tensile strength (TS), the elongation (El), the bore expansion ratio (λ) and the like, were obtained. The results are described in Table 2, Table 3 (continuation of Table 2), Table 4 and Table 5 (continuation of Table 4). The expansion ratios for hole λ in the tables were obtained from the following expression (L).
    λ (%) = {(d '- d) / d} x 100 (L) [0076] d': a hole diameter when a fracture penetrates the plate thickness d: an initial hole diameter.
    [0077] In addition, with regard to the types of galvanization in Table 2, CR represents a non-galvanized cold-rolled steel sheet, GI represents that galvanization is formed, GA represents that galvanizing is formed, EG represents that electro-galvanization is formed , and Al represents that aluminization is formed.
    [0078] In addition, the determinations G and B in the tables have the following meanings.
    [0079] G: a target condition expression is satisfied.
    [0080] B: the expression of target condition is not satisfied.
    [0081] In addition, provided that expression (H), expression (I) and
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    35/47 expression (J) are substantially the same as expression (B), expression (C) and expression (D) respectively, in the headings of the respective tables, expression (B), expression (C) and expression (D) are described as representative.
    Petition 870180160940, of 12/10/2018, p. 44/66 [Table 1]
    Steel type reference symbol Ç Si Mn P s N Al Cr Mo V You Nb Ni Ass Here B REM Expression(THE) THE Exemplo 0.042 0.145 1.55 0.003 0.008 0.0035 0.035 0 0 0 0 0 0 0 0 0 0 54.2 B 0.062 0.221 1.61 0.023 0.006 0.0064 0.021 0 0 0 0 0 0.3 0 0 0 0 44.6 Ç 0.144 0.950 2.03 0.008 0.009 0.0034 0.042 0.12 0 0 0 0 0 0 0 0 0 47.1 D 0.072 0.342 1.62 0.007 0.007 0.0035 0.042 0 0.15 0 0 0 0 0 0 0 0 46.3 AND 0.074 0.058 1.54 0.008 0.008 0.0045 0.034 0.21 0 0 0 0 0 0 0 0 0 24.7 F 0.081 0.256 1.71 0.006 0.009 0.0087 0.041 0 0 0 0 0 0 0.4 0.004 0 0 36.9 G 0.095 0.321 1.51 0.012 0.008 0.0041 0.038 0 0 0 0 0 0 0 0 0 0 32.8 H 0.090 0.465 1.51 0.051 0.001 0.0035 0.032 0.32 0.05 0 0 0 0 0 0.003 0 0 42.6 I 0.084 0.512 1.54 0.008 0.002 0.0065 0.041 0 0 0.03 0 0 0 0 0 0 0 48.8 J 0.075 0.785 1.62 0.007 0.009 0.0014 0.025 0 0.31 0 0 0 0 0 0 0 0 73.9 K 0.089 0.145 1.52 0.006 0.008 0.0026 0.034 0 0 0 0 0 0 0 0 0 0 25.2 L 0.098 0.624 2.11 0.012 0.006 0.0035 0.012 0 0.21 0 0.05 0 0 0 0 0 0 53.4 M 0.103 0.325 1.58 0.011 0.005 0.0032 0.025 0 0 0 0 0 0 0 0 0 0 31.1 N 0.101 0.265 2.61 0.009 0.008 0.0035 0.041 0 0.31 0 0 0 0 0 0 0.0015 0 38.9 O 0.142 0.955 1.74 0.007 0.007 0.0041 0.037 0 0.25 0 0 0 0 0 0 0 0 45.9 P 0.097 0.210 2.45 0.005 0.008 0.0022 0.045 0.42 0 0 0 0 0 0 0 0 0 36.1 Q 0.123 0.325 1.84 0.011 0.003 0.0037 0.035 0 0.11 0 0 0.01 0 0 0 0.0010 0 28.2 R 0.113 0.120 2.06 0.008 0.004 0.0047 0.035 0 0 0 0 0.03 0 0 0 0 0 23.5 s 0.134 0.562 1.86 0.013 0.007 0.0034 0.034 0 0.12 0 0 0 0 0 0 0 0 34.9 T 0.141 0.150 2.35 0.018 0.003 0.0029 0.031 0 0.21 0 0.03 0 0 0 0 0 0 22.0 U 0.128 0.115 2.41 0.011 0.003 0.0064 0.021 0 0.31 0 0 0 0 0 0 0.0008 0 23.3 W 0.142 0.562 2.03 0.012 0.007 0.0012 0.036 0 0 0 0 0 0 0 0.002 0 0 34.1 X 0.118 0.921 1.54 0.013 0.003 0.0087 0.026 0.15 0.11 0 0.05 0 0 0 0 0.0014 0.0005 52.1 Y 0.125 0.150 2.44 0.009 0.007 0.0087 0.034 0.32 0 0 0 0 0 0 0 0.0015 0 25.5 Z 0.145 0.110 2.31 0.008 0.004 0.0069 0.035 0 0.15 0.05 0 0 0 0 0 0 0 19.7
    36/47
    Petition 870180160940, of 12/10/2018, p. 45/66
    AA 0.075 0.210 1.85 0.010 0.005 0.0025 0.025 0 0 0 0 0 0 0 0 0 0 38.7 AB 0.085 0.210 1.84 0.011 0.005 0.0032 0.032 0 0 0 0 0 0 0 0 0 0 34.0 B.C 0.092 0.150 1.95 0.008 0.003 0.0035 0.035 0 0 0 0 0 0 0 0 0 0 29.3 AD 0.075 0.325 1.95 0.008 0.004 0.0034 0.031 0 0 0 0 0 0 0 0 0 0 47.7 AE 0.087 0.256 1.99 0.008 0.002 0.0030 0.031 0 0 0 0 0 0 0 0 0 0 37.6 AF 0.092 0.263 1.85 0.008 0.002 0.0030 0.031 0 0 0 0 0 0 0 0 0 0 34.4 AG ExampleComparative 0.111 0.526 1.85 0.007 0.003 0.0034 0.030 0 0 0 0 0 0 0 0 0 0 40.4 AH 0.028 0.321 1.55 0.007 0.003 0.0035 0.035 0 0 0 0 0 0 0 0 0 0.0006 112.7 THERE 0.252 0.512 2.15 0.003 0.006 0.0009 0.041 0 0 0 0 0 0 0 0 0 0 18.7 AJ 0.075 0.005 2.12 0.007 0.009 0.0035 0.035 0 0.15 0 0 0 0 0 0 0.0012 0 28.6 AK 0.081 1,521 1.50 0.008 0.005 0.0034 0.026 0.28 0.32 0 0 0 0 0 0 0.0015 0 112.4 AL 0.099 0.660 0.08 0.009 0.003 0.0032 0.029 0 0 0 0 0 0 0 0 0 0 34.1 AM 0.125 0.050 2.81 0.007 0.004 0.0034 0.036 0 0 0 0 0 0 0 0 0 0 24.5 AN 0.131 0.321 2.05 0.091 0.003 0.0021 0.034 0.26 0.15 0 0 0.03 0 0 0 0 0 27.9
    37/47
    Petition 870180160940, of 12/10/2018, p. 46/66
    TO
    0.064
    0.125
    2.50
    0.002
    0.022
    0.0059
    0.034
    0.2
    48.8
    AP
    0.039
    0.265
    1.52
    0.011
    0.009
    0.0152
    0.026
    0.02
    0.003
    72.9
    AQ
    0.144
    0.012
    2.39
    0.007
    0.004
    0.0065
    0.003
    0.20
    17.0
    AIR
    0.142
    0.150
    2.35
    0.005
    0.003
    0.0035
    0.060
    0.22
    21.8
    AT
    0.149
    0.020
    1.50
    0.005
    0.003
    0.0020
    0.025
    0.001
    10.7
    AT
    0.132
    0.090
    2.05
    0.005
    0.003
    0.0020
    0.025
    0.01
    18.9
    AU
    0.135
    0.220
    2.06
    0.005
    0.003
    0.0020
    0.025
    0.01
    23.4
    38/47
    Petition 870180160940, of 12/10/2018, p. 47/66
    Table 2
    Steel type reference symbol Test reference symbol Annealing temperature (° C) After annealing and hardening lamination and before hot stamping Fraction of perlite area before cold rolling (%) TS(MPa) EL(%) λ (%) TS xEL TS x λ Fraction areaferrite(%) Fraction of martensite area (%) Ferrite area fraction+ martensite (%) Fraction of residual austenite area (%) Fraction areabainite(%) Fraction areaperlite(%) THE 1 750 485 32.5 111 15763 53835 88 11 99 1 0 0 35 B 2 750 492 33.2 107 16334 52644 78 15 93 3 4 0 25 Ç 3 720 524 30.5 99 15982 51876 75 10 85 4 5 6 34 D 4 745 562 34.2 95 19220 53390 74 15 89 3 8 0 25 AND 5 775 591 29.8 90 17612 53190 70 15 85 4 11 0 56 F 6 780 601 25.5 84 15326 50484 74 10 84 3 5 8 62 G 7 741 603 26.1 83 15738 50049 70 10 80 5 6 9 75 H 8 756 612 32.1 88 19645 53856 71 15 86 3 8 3 35 I 9 778 614 28.1 90 17253 55260 75 12 87 4 5 4 42 J 10 762 615 30.5 91 18758 55965 78 12 90 3 7 0 25 K 11 761 621 24.2 81 15028 50301 71 10 81 4 7 8 35 L 12 745 633 31.6 84 20003 53172 81 12 93 2 5 0 15 M 13 738 634 32.4 85 20542 53890 51 35 86 3 5 6 8 N 14 789 642 28.6 84 18361 53928 50 34 84 4 5 7 42 O 15 756 653 29.8 81 19459 52893 72 19 91 3 6 0 33 P 16 785 666 27.5 79 18315 52614 68 28 96 3 1 0 25 Q 17 777 671 26.5 80 17782 53680 52 41 93 3 4 0 34 R 18 746 684 21.5 80 14706 54720 51 35 86 4 10 0 52 s 19 789 712 24.1 74 17159 52688 48 38 86 4 10 0 46 T 20 785 745 28.5 71 21233 52895 44 41 85 3 12 0 18 U 21 746 781 20.2 69 15776 53889 41 42 83 5 12 0 22 W 22 845 812 17.4 65 14129 52780 45 39 84 4 12 0 15 X 23 800 988 17.5 55 17290 54340 42 46 88 2 5 5 45 Y 24 820 1012 17.4 54 17609 54648 41 41 82 2 16 0 42 Z 25 836 1252 13.5 45 16902 56340 41 48 89 2 9 0 10
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    Petition 870180160940, of 12/10/2018, p. 48/66
    1/47
    Table 3
    Steel type reference symbol Test reference symbol Annealing temperature (° C) After annealing and hardening lamination and before hot stamping Fraction of perlite area before cold rolling (%) TS(MPa) EL(%) λ(%) TS xEL TS x λ Fractioninareainferrite(%) Fraction of martensite area (%) Fraction of ferrite + martensite area (%) Fraction of residual austenite area (%) Fractioninareainbainite(%) Fraction of perlite area (%) AA 26 794 625 24.4 72 15250 45000 59 10 69 2 16 13 27 AB 27 777 626 27.1 64 16965 40064 56 15 71 1 11 17 30 B.C 28 754 594 28.0 78 16632 46332 58 12 70 2 14 14 24 AD 29 749 627 21.6 62 13543 38874 37 19 56 1 24 19 36 AE 30 783 627 24.9 71 15612 44517 66 10 76 2 10 12 21 AF 31 748 683 24.3 72 16597 49176 59 21 80 2 8 10 46 AG 32 766 632 28.6 58 18075 36656 69 20 89 2 9 0 25 AH 33 768 326 41.9 112 13659 36512 95 0 95 3 2 0 2 THERE 34 781 1512 8.9 25 13457 37800 5 90 95 4 1 0 3 AJ 35 739 635 22.5 72 14288 45720 74 22 96 2 2 0 42 AK 36 789 625 31.2 55 19500 34375 75 22 97 2 1 0 15 AL 37 784 705 26.0 48 18330 33840 42 25 67 1 25 7 2 AM 38 746 795 15.6 36 12402 28620 30 52 82 3 10 5 14 AN 39 812 784 19.1 42 14974 32928 51 37 88 3 9 0 16 TO 40 826 602 30.5 35 18361 21070 68 21 89 4 7 0 22 AP 41 785 586 27.4 66 16056 38676 69 21 90 4 6 0 32 AQ 42 845 1254 7.5 25 9405 31350 11 68 79 4 11 6 22 AIR 43 775 1480 9.6 26 14208 38480 12 69 81 3 16 0 5 AT 45 778 1152 12.0 42 13824 48384 41 35 76 0 23 1 5 AT 46 688 855 15.9 53 13595 45315 30 20 50 1 19 30 40 AU 47 893 1349 6.3 35 8499 47215 5 51 56 1 41 2 5
    40/47
    Petition 870180160940, of 12/10/2018, p. 49/66
    Table 4
    Steel type reference symbol Test reference symbol After hot stamping Plating type *) TS(MPa) EL(%) λ(%) TS xEL TS x λ Fraction areaferrite(%) Fraction of martensite area (%) Fraction of ferrite + martensite area (%) Fraction of residual austenite area (%) Fraction areabainite(%) Fraction of perlite area (%) THE 1 445 41.2 125 18334 55625 87 11 98 1 0 1 CR B 2 457 40.5 118 18509 53926 76 15 91 3 4 2 GA Ç 3 532 35.2 101 18726 53732 75 10 85 1 5 9 GI D 4 574 33.3 96 19114 55104 74 15 89 3 8 0 EG AND 5 591 30.9 86 18262 50826 69 15 84 1 11 4 THERE F 6 605 30.1 88 18211 53240 82 10 92 3 5 0 CR G 7 611 30.8 87 18819 53157 75 15 90 1 6 3 CR H 8 612 32.0 85 19584 52020 80 15 95 3 0 2 GA I 9 785 25.3 65 19861 51025 56 15 71 4 23 2 GA J 10 795 23.5 65 18683 51675 55 25 80 1 19 0 GA K 11 815 23.5 71 19153 57865 50 32 82 1 17 0 GA L 12 912 22.5 63 20520 57456 45 33 78 2 20 0 GI M 13 975 20.6 60 20085 58500 50 41 91 3 5 1 GA N 14 992 19.2 52 19046 51584 52 34 86 4 5 5 GA O 15 1005 18.6 51 18693 51255 48 40 88 3 6 3 GI P 16 1012 17.8 52 18014 52624 42 28 70 1 29 0 GA Q 17 1023 18.2 50 18619 51150 46 41 87 3 4 6 GA R 18 1031 18.0 55 18558 56705 51 35 86 4 10 0 CR s 19 1042 20.5 48 21361 50016 52 38 90 4 0 6 GA T 20 1125 18.5 48 20813 54000 41 41 82 3 12 3 GI U 21 1185 16.0 45 18960 53325 42 42 84 1 12 3 EG W 22 1201 15.6 46 18736 55246 43 39 82 4 12 2 GA X 23 1224 14.9 41 18238 50184 41 46 87 2 10 1 THERE Y 24 1342 13.5 40 18117 53680 41 41 82 1 16 1 GA Z 25 1482 12.5 40 18525 59280 41 48 89 1 9 1 CR
    41/47
    Petition 870180160940, of 12/10/2018, p. 50/66
    Table 5
    Steel type reference symbol Test reference symbol After hot stamping Plating type *) TS(MPa) EL(%) λ(%) TS xEL TS x λ Fraction areaferrite(%) Fraction of martensite area (%) Fraction of ferrite + martensite area (%) Fraction of residual austenite area (%) Fraction areabainite(%) Fraction of perlite area (%) AA 26 814 18.9 61 15385 49654 39 44 83 2 4 11 GA AB 27 991 17.1 47 16946 46577 37 47 84 1 3 12 CR B.C 28 1004 16.5 47 16566 47188 36 44 80 2 7 11 GA AD 29 1018 15.9 43 16186 43774 31 42 73 1 8 18 EG AE 30 1018 16.3 48 16593 48864 43 40 83 2 3 12 GI AF 31 1184 14.2 42 16813 49728 33 46 79 2 9 10 THERE AG 32 715 18.5 55 13228 39325 69 18 87 2 9 2 CR AH 33 440 42.5 105 18700 46200 95 0 95 3 2 0 GA THERE 34 1812 8.5 26 15402 47112 ’ 5 90 95 4 1 0 GA AJ 35 812 18.5 50 15022 40600 60 22 82 2 15 1 GA AK 36 1012 17.2 41 17406 41492 55 42 97 2 1 0 GA AL 37 1005 16.5 35 16583 35175 45 41 86 3 10 1 GI AM 38 1002 15.0 41 15030 41082 45 41 86 3 10 1 GI AN 39 1015 18.2 41 18473 41615 51 37 88 3 9 0 GI TO 40 1111 17.0 36 18887 39996 50 30 80 4 7 9 GI AP 41 566 31.0 71 17546 40186 48 40 88 4 6 2 EG AQ 42 1312 11.1 31 14563 40672 11 68 79 4 11 6 THERE AIR 43 1512 10.2 31 15422 46872 12 69 81 3 16 0 GA AT 45 1242 10.0 39 12420 48438 41 32 73 3 21 3 GA AT 46 991 13.1 40 12982 39640 24 34 58 1 14 27 GA AU 47 1326 8.9 31 11801 41106 6 69 75 3 21 1 GA
    42/47
    Petition 870180160940, of 12/10/2018, p. 51/66
    Table 6
    Steel type reference symbol Test reference symbol Left side of expression (B) Determinenation Left side of expression (B) after hot stamping Determines-dog Left side of expression (C) Determines-dog Left side of expression (C) after hot stamping Deter-mining MnS area fraction of 0.1 gm or more before hot stamping (%) MnS area fraction of 0.1 gm or more after hot stamping (%) THE 1 1.02 G 1.03 G 15 G 16 G 0.005 0.005 B 2 1.03 G 1.03 G 18 G 17 G 0.006 0.006 Ç 3 1.09 G 1.08 G 2 G 3 G 0.014 0.013 D 4 1.04 G 1.04 G 19 G 18 G 0.006 0.006 AND 5 1.06 G 1.05 G 14 G 14 G 0.008 0.008 F 6 1.09 G 1.09 G 13 G 13 G 0.013 0.013 G 7 1.09 G 1.08 G 10 G 9 G 0.009 0.008 H 8 1.06 G 1.06 G 8 G 8 G 0.005 0.005 I 9 1.04 G 1.04 G 7 G 8 G 0.006 0.006 J 10 1.03 G 1.02 G 12 G 11 G 0.007 0.007 K 11 1.02 G 1.03 G 16 G 16 G 0.006 0.006 L 12 1.02 G 1.03 G 15 G 16 G 0.008 0.008 M 13 1.09 G 1.08 G 12 G 12 G 0.011 0.011 N 14 1.07 G 1.07 G 13 G 14 G 0.003 0.003 O 15 1.08 G 1.08 G 11 G 11 G 0.002 0.002 P 16 1.06 G 1.06 G 10 G 10 G 0.005 0.005 Q 17 1.05 G 1.06 G 11 G 11 G 0.006 0.006 R 18 1.03 G 1.03 G 17 G 16 G 0.007 0.007 s 19 1.07 G 1.07 G 18 G 18 G 0.008 0.008 T 20 1.09 G 1.08 G 10 G 10 G 0.004 0.004 U 21 1.09 G 1.09 G 5 G 6 G 0.012 0.012 W 22 1.08 G 1.08 G 6 G 6 G 0.006 0.006 X 23 1.07 G 1.06 G 12 G 8 G 0.007 0.007 Y 24 1.06 G 1.06 G 10 G 10 G 0.005 0.005 Z 25 1.04 G 1.03 G 15 G 17 G 0.006 0.006
    43/47
    Petition 870180160940, of 12/10/2018, p. 52/66
    Table 7
    Steel type reference symbol Test reference symbol Left side of expression (B) Determinenation Left side of expression (B) after hot stamping Determines-dog Left side of expression (C) Determines-dog Left side of expression (C) after hot stamping Deter-mining MnS area fraction of 0.1 pm or more before hot stamping (%) MnS area fraction of 0.1 pm or more after hot stamping (%) AA 26 1.12 B 1.12 B 21 B 21 B 0.010 0.010 AB 27 1.14 B 1.13 B 23 B 22 B 0.008 0.008 B.C 28 1.11 B 1.11 B 20 B 20 B 0.006 0.006 AD 29 1.17 B 1.16 B 25 B 25 B 0.007 0.007 AE 30 1.13 B 1.13 B 22 B 21 B 0.009 0.009 AF 31 1.10 B 1.09 G 20 B 19 G 0.002 0.002 AG 32 1.12 B 1.13 B 22 B 23 B 0.003 0.003 AH 33 1.15 B 1.15 B 21 B 21 B 0.004 0.004 THERE 34 1.23 B 1.18 B 25 B 25 B 0.006 0.006 AJ 35 1.21 B 1.21 B 22 B 22 B 0.007 0.007 AK 36 1.14 B 1.14 B 21 B 21 B 0.008 0.007 AL 37 0.36 B 0.37 B 31 B 30 B 0.006 0.006 AM 38 1.36 B 1.37 B 32 B 31 B 0.006 0.006 AN 39 1.23 B 1.25 B 25 B 28 B 0.009 0.008 TO 40 1.35 B 1.33 B 30 B 35 B 0.004 0.004 AP 41 1.05 G 1.04 G 12 G 11 G 0.006 0.006 AQ 42 1.15 B 1.16 B 21 B 25 B 0.003 0.003 AIR 43 1.08 G 1.08 G 18 G 18 G 0.002 0.002 AT 45 1.19 B 1.17 B 24 B 23 B 0.005 0.005 AT 46 1.29 B 1.28 B 28 B 27 B 0.004 0.005 AU 47 1.09 G 1.09 G 19 G 19 G 0.005 0.005
    44/47
    Petition 870180160940, of 12/10/2018, p. 53/66
    Tabe a 8
    Yes-cake Yes-cake Before hot stamping After hot stamping Sidees- In-Tue- Sidees- CT Sideright In-Tue- Tem-rura Warm-up time Sidees- In-finish inreferred toreferenceoftypeinsteel inreferred toreferenceofsteel n10 n20 Sidees-dear ofex-pres-are(D) In-Tue-mi-at-dog n1 n2 Sidees-dear ofex-pres-are(D) In-Tue-mine-dog deargivesexpression (E) mi-at-dog dear ofex-pres-are(F) givesex-pres-are(F) mine-dog inthat-cementgivesfurnace (° C) internal furnace heating cement (minutes) dear ofex-pres-are(G) nation THE 1 9 13 1.4 G 9 12 1.3 G 1.4 G 401 550 679 G 1200 85 1918 G B 2 3 4 1.3 G 3 4 1.3 G 1.2 G 386 620 668 G 1250 102 1948 G Ç 3 2 3 1.5 B 2 3 1.5 B 1.1 G 307 542 600 G 1154 152 1317 B D 4 6 7 1.2 G 5 6 1.2 G 1.4 G 377 553 653 G 1123 124 1748 G AND 5 2 2 1.0 G 2 2 1.0 G 1.6 G 382 632 657 G 1215 136 2231 G F 6 2 2 1.0 G 2 2 1.0 G 1.2 G 368 664 654 B 1223 127 1873 G G 7 1 1 1.0 G 1 1 1.0 G 1.3 G 379 701 668 B 1123 111 1831 G H 8 5 5 1.0 G 5 6 1.2 G 1.2 G 374 631 643 G 1156 106 1778 G I 9 4 5 1.3 G 4 5 1.3 G 1.7 G 382 558 669 G 1148 95 1670 G J 10 3 4 1.3 G 3 4 1.3 G 1.4 G 372 559 639 G 1206 87 1522 G K 11 7 7 1.0 G 7 8 1.1 G 1.1 G 381 674 669 B 1214 152 2235 G L 12 5 6 1.2 G 5 6 1.2 G 1.3 G 319 452 597 G 1233 182 1524 G M 13 11 19 1.7 B 11 18 1.6 B 1.3 G 369 442 660 G 1112 47 1422 B N 14 6 7 1.2 G 6 8 1.3 G 1.2 G 271 512 543 G 1287 252 1513 G O 15 2 2 1.0 G 2 2 1.0 G 1.6 G 331 612 615 G 1250 122 1535 G P 16 4 5 1.3 G 4 5 1.3 G 1.7 G 285 487 554 G 1285 222 1587 G Q 17 7 8 1.1 G 7 9 1.3 G 1.9 G 334 566 622 G 1156 135 1642 G R 18 16 19 1.2 G 15 18 1.2 G 1.4 G 321 567 614 G 1222 185 1761 G s 19 11 12 1.1 G 10 12 1.2 G 1.3 G 327 554 617 G 1232 122 1589 G T 20 6 7 1.2 G 6 7 1.2 G 1.1 G 277 512 564 G 1256 152 1522 G U 21 7 14 2.0 B 7 13 1.9 B 1.2 G 277 521 554 G 1256 138 1472 B W 22 17 21 1.2 G 15 20 1.3 G 1.1 G 310 571 609 G 1250 145 1550 G X 23 23 27 1.2 G 22 25 1.1 G 1.2 G 360 656 640 B 1150 138 1600 G Y 24 21 28 1.3 G 20 28 1.4 G 1.4 G 275 522 554 G 1260 182 1526 G Z 25 26 33 1.3 G 25 32 1.3 G 1.5 G 280 504 571 G 1250 151 1554 G
    45/47
    Petition 870180160940, of 12/10/2018, p. 54/66
    Tabe a 9
    Yes-cakeinreferred toreferenceoftypeinsteel Yes-cakeinreferred tores-coofsteel Before hot stamping After hot stamping Sidees-dear ofex-pres-are(AND) Deter-mining Sidees-dear ofex-pres-are(F) CT There-ofdi-reitogivesex-presare(F) Deter-mine-dog Tem-rurainthat-cementgivesfurnace (° C) Internal heating time of furnace heating (minutes) Sidees-dear ofex-pres-are(G) In-finishnation n10 n20 Sidees-dear ofex-pres-are(D) In-Tue-mine-dog n1 n2 Sidees-dear ofex-pres-are(D) In-Tue-mi-at-dog AA 26 12 14 1.2 G 12 15 1.3 G 0.9 B 358 602 643 G 1200 132 1746 G AB 27 9 13 1.4 G 9 13 1.4 G 0.8 B 354 505 641 G 1200 126 1739 G B.C 28 14 18 1.3 G 14 19 1.4 G 0.8 B 341 506 630 G 1188 133 1677 G AD 29 5 7 1.4 G 5 7 1.4 G 0.6 B 349 443 634 G 1165 145 1593 G AE 30 12 16 1.3 G 12 15 1.3 G 0.7 B 340 611 627 G 1152 152 1590 G AF 31 17 23 1.4 G 16 22 1.4 G 1.0 B 350 352 639 G 1187 89 1563 G AG 32 5 6 1.2 G 5 7 1.4 G 0.9 B 341 555 634 G 1201 152 1644 G AH 33 3 4 1.3 G 3 4 1.3 G 1.1 G 407 436 683 G 1203 125 1965 G THERE 34 12 16 1.3 G 12 15 1.3 G 1.1 G 247 541 568 G 1250 175 1549 G AJ 35 16 21 1.3 G 15 20 1.3 G 1.3 G 331 577 607 G 1200 96 1518 G AK 36 11 13 1.2 G 11 12 1.1 G 1.2 G 375 578 628 G 1201 166 1508 G AL 37 12 18 1.5 G 12 17 1.4 G 1.1 G 506 578 796 G 1285 205 8593 G AM 38 15 20 1.3 G 14 20 1.4 G 1.2 G 248 533 543 G 1285 312 1529 G AN 39 10 11 1.1 G 10 12 1.2 G 1.1 G 305 580 580 G 1212 125 1538 G TO 40 9 11 1.2 G 8 11 1.4 G 1.2 G 302 564 578 G 1285 185 1535 G AP 41 6 8 1.3 G 6 8 1.3 G 1.1 G 405 582 683 G 1200 135 2066 G AQ 42 12 14 1.2 G 12 15 1.3 G 1.1 G 273 477 560 G 1250 166 1568 G AIR 43 21 24 1.1 G 22 25 1.1 G 1.5 G 277 504 563 G 1254 222 1634 G AT 45 17 19 1.1 G 15 18 1.2 G 1.3 G 354 620 655 G 1224 201 2526 G AT 46 16 16 1.0 G 15 17 1.1 G 1.3 G 313 550 610 G 1199 201 1779 G AU 47 16 19 1.2 G 15 18 1.2 G 1.6 G 311 552 608 G 1184 201 1687 G
    46/47
    Petition 870180160940, of 12/10/2018, p. 55/66
    47/47 [0082] Based on the examples described above, considering that the conditions of the present invention are satisfied, it is possible to obtain a hot stamped steel for which an excellent cold rolled steel sheet for hot stamping, an excellent sheet galvanized cold-rolled steel sheet for hot stamping, an excellent hot-dip galvanized steel sheet for hot stamping, an excellent electrogalvanized cold-rolled steel sheet for hot stamping, or an excellent aluminized cold-rolled steel sheet for hot stamping, all of which satisfy TS x λ> 50000 MPa-%, is used, even after hot stamping. Industrial Applicability [0083] As long as the hot stamped steel, which is obtained in the present invention, and for which the cold rolled steel sheet for hot stamping is used, it can satisfy TS x λ,> 50000 MPa-% after stamping When hot, hot stamped steel has high pressing operability and high strength, and meets the current requirements for a vehicle, such as additional weight reduction and more complicated molding of a component.
    Brief Description of the Reference Symbols
    S1: FUSION PROCESS
    S2: CASTING PROCESS
    S3: HEATING PROCESS
    S4: HOT LAMINATION PROCESS
    S5: COILING PROCESS
    S6: STRIPPING PROCESS
    S7: COLD LAMINATION PROCESS
    S8: RECOVERY PROCESS
    S9: CRUISE LAMINATION PROCESS
    S10: GALVANIZATION PROCESS
    S11: ALLOY PROCESS
    S12: ALUMINIZATION PROCESS
    S13: ELECTROGALVANIZATION PROCESS
    Petition 870180160940, of 12/10/2018, p. 56/66
    权利要求:
    Claims (13)
    [1]
    claims
    1. Hot stamped steel, characterized by the fact that it consists of, by mass%:
    C: 0.030% to 0.150%;
    Si: 0.010% to 1.00%;
    Mn: 1.50% to 2.70%;
    P: 0.001% to 0.060%;
    S: 0.001% to 0.010%;
    N: 0.0005% to 0.0100%;
    Al: 0.010% to 0.050%, and optionally, one or more of B: 0.0005% to 0.0020%;
    Mo: 0.01% to 0.50%;
    Cr: 0.01% to 0.50%;
    V: 0.001% to 0.100%;
    Ti: 0.001% to 0.100%;
    Nb: 0.001% to 0.050%;
    Ni: 0.01% to 1.00%;
    Cu: 0.01% to 1.00%;
    Ca: 0.0005% to 0.0050%;
    REM: 0.0005% to 0.0050%, and a surplus of Fe and unavoidable impurities, in which when [C] represents an amount of C by mass%, [Si] represents an amount of Si by mass%, and [Mn] represents an amount of Mn per% by mass, the following expression (A) is satisfied, a metallographic structure after hot stamping includes 40% to 90% of a ferrite, and 10% to 60% of a martensite in a fraction of area, a total of a fraction of ferrite area, and a fraction of
    Petition 870180160940, of 12/10/2018, p. 57/66
    [2]
    2/5 area of the martensite is 60% or more, the metallographic structure optionally additionally includes one or more than 10% or less of a perlite in a fraction of area, 5% or less of a residual austenite in a volume ratio , and less than 40% of a bainite as a surplus in a fraction of area, a martensite hardness measured with a nanoendentator satisfies the following expression (B), and the following expression (C),
    TS x λ which is a product of a tensile strength TS and a bore expansion ratio λ is 50000 MPa-% or more, (5 x [Si] + [Mn]) / [C]> 11 (A),
    H2 / H1 <1.10 (B), σΗΜ <20 (C), and H1 is an average hardness of martensite on a surface part of a sheet thickness after hot stamping, H2 is an average hardness of martensite in a central part of the sheet thickness which is an area having a width of 200 pm in one direction of the thickness in a center of the sheet thickness after hot stamping, and σΗΜ is a variation of the average hardness of the martensite in the part plate thickness after hot stamping.
    2. Hot stamped steel according to claim 1, characterized by the fact that a fraction of the MnS area in the hot stamped steel and having an equivalent circle diameter from 0.1 pm to 10 pm is 0.01 % or less, the following expression (D) is satisfied, n2 / n1 <1.5 (D), and n1 is an average number density per 10,000 pm 2 of MnS having an equivalent circle diameter of 0.1 pm at 10 pm on
    Petition 870180160940, of 12/10/2018, p. 58/66
    [3]
    3/5 a 1/4 part of the plate thickness after hot stamping, and n2 is an average number density per 10,000 pm 2 of MnS having the equivalent circle diameter of 0.1 pm to 10 pm on the part plate thickness after hot stamping.
    3. Hot stamped steel according to claim 1 or 2, characterized by the fact that a hot dip galvanization is formed on a surface of the same.
    [4]
    4. Hot stamped steel according to claim 3, characterized by the fact that a hot dip galvanizing is formed on a surface of hot dip galvanizing.
    [5]
    5. Hot stamped steel according to claim 1 or 2, characterized by the fact that an electrogalvanization is formed on a surface thereof.
    [6]
    6. Hot stamped steel according to claim 1 or 2, characterized by the fact that an aluminization is formed on a surface of the same.
    [7]
    7. Method for the production of hot-stamped steel, the method characterized by the fact that it comprises:
    subjecting the steel to continuous casting having a chemical composition as defined in claim 1, and obtaining a steel;
    heat the steel;
    hot rolling steel with a hot rolling installation including a plurality of supports;
    winding steel after hot rolling;
    stripping the steel after winding;
    cold rolling steel with a cold rolling installation including a plurality of supports after blasting under a condition that meets the following expression (E);
    annealing in which the steel is annealed under 700 ° C to 850 ° C, and cooled after cold rolling;
    Petition 870180160940, of 12/10/2018, p. 59/66
    4/5 subject the steel to hardening lamination after cooling and then annealing; and hot stamping in which the steel is heated to a temperature range of 700 ° C to 1000 ° C at a rate of temperature increase of 5 ° C / second to 500 ° C / second after hardening lamination, hot stamped within the temperature range after a waiting time of 1 second to 120 seconds, and then cooled to room temperature or more, and 300 ° C or less to the cooling rate of 10 ° C / second to 1000 ° C / second,
    1.5 x r1 / r + 1.2 x r2 / r + r3 / r> 1.0 (E), and the ri (i = 1, 2, 3) represents an individual target cold rolling reduction in one i-th support (i = 1, 2, 3) counted from a more superior support among the plurality of supports in cold rolling in unit%, and r represents a reduction of total cold rolling in cold rolling in unit% , in which cold rolling is performed while controlling the desired cold rolling reduction and a real cold rolling reduction to become the same value.
    [8]
    8. Method for the production of hot-stamped steel, according to claim 7, characterized by the fact that when CT represents a winding temperature in the winding unit ° C, [C] represents the amount of C by mass%, [Mn] represents the amount of Mn per% by mass, [Cr] represents the amount of Cr by% by mass, and [Mo] represents the amount of Mo by% by mass in the steel plate, the following expression (F) is satisfied,
    560 - 474 x [C] - 90 x [Mn] - 20 x [Cr] - 20 x [Mo] <CT <830 - 270 x [C] - 90 x [Mn] - 70 x [Cr] - 80 x [Mo] (F).
    [9]
    9. Method for the production of hot stamped steel, according to claim 8, characterized by the fact that
    Petition 870180160940, of 12/10/2018, p. 60/66
    5/5 when T represents a heating temperature in the heating unit of ° C, t represents an internal furnace time in the heating unit in minute, [Mn] represents the amount of Mn per% by mass, and [S] represents an amount of S per weight% on the steel plate, the following expression (G) is satisfied,
    T x ln (t) / (1.7 x [Mn] + [S])> 1500 (G).
    [10]
    10. Method for producing hot stamped steel according to any one of claims 7 to 9, characterized by the fact that it additionally comprises:
    galvanize the steel between annealing and hardening lamination.
    [11]
    11. Method for the production of hot stamped steel, according to claim 10, characterized by the fact that it additionally comprises:
    connect the steel between galvanizing and hardening lamination.
    [12]
    12. Method for the production of hot-stamped steel according to any one of claims 7 to 9, characterized in that it additionally comprises:
    electrogalvanize steel after hardening lamination.
    [13]
    13. Method for producing hot stamped steel according to any one of claims 7 to 9, characterized by the fact that it additionally comprises:
    aluminize the steel between annealing and hardening lamination.
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    同族专利:
    公开号 | 公开日
    WO2013105633A1|2013-07-18|
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    BR112014017100A2|2017-06-13|
    BR112014017100A8|2017-07-04|
    ES2666968T3|2018-05-08|
    KR20140102308A|2014-08-21|
    TW201335385A|2013-09-01|
    EP2803748B1|2018-03-14|
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    ZA201404812B|2016-01-27|
    TWI458838B|2014-11-01|
    CN104040011B|2016-06-22|
    RU2014129486A|2016-03-10|
    EP2803748A4|2016-06-29|
    EP2803748A1|2014-11-19|
    CA2862829C|2017-09-12|
    US9945013B2|2018-04-17|
    RU2581330C2|2016-04-20|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPH06128688A|1992-10-20|1994-05-10|Sumitomo Metal Ind Ltd|Hot rolled steel plate excellent in fatigue characteristic and it production|
    JP3731315B2|1997-09-16|2006-01-05|フジノン株式会社|Ultrasound probe inserted endoscopically|
    JP3755301B2|1997-10-24|2006-03-15|Ｊｆｅスチール株式会社|High-strength, high-workability hot-rolled steel sheet excellent in impact resistance, strength-elongation balance, fatigue resistance and hole expansibility, and method for producing the same|
    JP3769143B2|1999-05-06|2006-04-19|新日本製鐵株式会社|Hot-rolled steel sheet for machining excellent in fatigue characteristics and method for producing the same|
    JP4414563B2|2000-06-12|2010-02-10|新日本製鐵株式会社|High-strength steel sheet excellent in formability and hole expansibility and method for producing the same|
    CN1190513C|2000-06-20|2005-02-23|杰富意钢铁株式会社|Thin steel sheet and method for prodn. thereof|
    FR2830260B1|2001-10-03|2007-02-23|Kobe Steel Ltd|DOUBLE-PHASE STEEL SHEET WITH EXCELLENT EDGE FORMABILITY BY STRETCHING AND METHOD OF MANUFACTURING THE SAME|
    JP4635525B2|2003-09-26|2011-02-23|Ｊｆｅスチール株式会社|High-strength steel sheet excellent in deep drawability and manufacturing method thereof|
    KR101094594B1|2003-09-30|2011-12-15|신닛뽄세이테쯔 카부시키카이샤|High-yield-ratio high-strength cold rolled steel sheet excelling in weldability and ductility|
    JP4317418B2|2003-10-17|2009-08-19|新日本製鐵株式会社|High strength thin steel sheet with excellent hole expandability and ductility|
    JP2005126733A|2003-10-21|2005-05-19|Nippon Steel Corp|Steel sheet for hot press having excellent hot workability, and automotive member|
    US7981224B2|2003-12-18|2011-07-19|Nippon Steel Corporation|Multi-phase steel sheet excellent in hole expandability and method of producing the same|
    JP4473587B2|2004-01-14|2010-06-02|新日本製鐵株式会社|Hot-dip galvanized high-strength steel sheet with excellent plating adhesion and hole expandability and its manufacturing method|
    JP4510488B2|2004-03-11|2010-07-21|新日本製鐵株式会社|Hot-dip galvanized composite high-strength steel sheet excellent in formability and hole expansibility and method for producing the same|
    JP4293020B2|2004-03-15|2009-07-08|Ｊｆｅスチール株式会社|Manufacturing method of high-strength steel sheet with excellent hole expandability|
    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|
    US11155902B2|2006-09-27|2021-10-26|Nucor Corporation|High strength, hot dip coated, dual phase, steel sheet and method of manufacturing same|
    WO2008110670A1|2007-03-14|2008-09-18|Arcelormittal France|Steel for hot working or quenching with a tool having an improved ductility|
    JP5223360B2|2007-03-22|2013-06-26|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|
    CA2697226C|2007-10-25|2015-12-15|Jfe Steel Corporation|High tensile strength galvanized steel sheet excellent in formability and method for manufacturing the same|
    US9376738B2|2007-10-29|2016-06-28|Nippon Steel & Sumitomo Metal Corporation|Hot forging use non-heat-treated steel and hot forged non-heat-treated steel part|
    WO2009090443A1|2008-01-15|2009-07-23|Arcelormittal France|Process for manufacturing stamped products, and stamped products prepared from the same|
    JP5365217B2|2008-01-31|2013-12-11|Ｊｆｅスチール株式会社|High strength steel plate and manufacturing method thereof|
    JP5167487B2|2008-02-19|2013-03-21|Ｊｆｅスチール株式会社|High strength steel plate with excellent ductility and method for producing the same|
    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|
    ES2526974T3|2008-04-10|2015-01-19|Nippon Steel & Sumitomo Metal Corporation|High strength steel sheets that have an excellent balance between hole expandability and ductility and also excellent fatigue resistance, zinc coated steel sheets and processes for producing steel sheets|
    US8128762B2|2008-08-12|2012-03-06|Kobe Steel, Ltd.|High-strength steel sheet superior in formability|
    JP5418047B2|2008-09-10|2014-02-19|Ｊｆｅスチール株式会社|High strength steel plate and manufacturing method thereof|
    JP5347392B2|2008-09-12|2013-11-20|Ｊｆｅスチール株式会社|Hot press member excellent in ductility, steel plate for hot press member, and method for producing hot press member|
    JP5418168B2|2008-11-28|2014-02-19|Ｊｆｅスチール株式会社|High-strength cold-rolled steel sheet excellent in formability, high-strength hot-dip galvanized steel sheet, and production method thereof|
    EP2436797B1|2009-05-27|2017-01-04|Nippon Steel & Sumitomo Metal Corporation|High-strength steel sheet, hot-dipped steel sheet, and alloy hot-dipped steel sheet that have excellent fatigue, elongation, and collision characteristics, and manufacturing method for said steel sheets|
    JP5740847B2|2009-06-26|2015-07-01|Ｊｆｅスチール株式会社|High-strength hot-dip galvanized steel sheet and manufacturing method thereof|
    JP5363922B2|2009-09-03|2013-12-11|株式会社神戸製鋼所|High-strength cold-rolled steel sheet with an excellent balance between elongation and stretch flangeability|
    ES2614806T3|2010-01-13|2017-06-02|Nippon Steel & Sumitomo Metal Corporation|Method for manufacturing high strength steel sheet that has excellent conformability|
    JP5521562B2|2010-01-13|2014-06-18|新日鐵住金株式会社|High-strength steel sheet with excellent workability and method for producing the same|
    CA2787575C|2010-01-26|2015-03-31|Kohichi Sano|High-strength cold-rolled steel sheet and method of manufacturing thereof|
    JP5114760B2|2010-03-31|2013-01-09|新日鐵住金株式会社|High-strength hot-dip galvanized steel sheet with excellent formability and method for producing the same|
    JP4962594B2|2010-04-22|2012-06-27|Ｊｆｅスチール株式会社|High-strength hot-dip galvanized steel sheet excellent in workability and manufacturing method thereof|
    JP5510057B2|2010-05-10|2014-06-04|新日鐵住金株式会社|Hot-dip galvanized steel sheet and manufacturing method thereof|
    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|
    EP2719787B1|2011-06-10|2016-04-13|Kabushiki Kaisha Kobe Seiko Sho|Hot press molded article, method for producing same, and thin steel sheet for hot press molding|
    CN104040010B|2012-01-13|2016-06-15|新日铁住金株式会社|The manufacture method of cold-rolled steel sheet and cold-rolled steel sheet|
    BR112014017100B1|2012-01-13|2019-04-24|Nippon Steel & Sumitomo Metal Corporation|HOT STAMPED STEEL AND METHOD FOR HOT STAMPED PRODUCTION|BR112014017100B1|2012-01-13|2019-04-24|Nippon Steel & Sumitomo Metal Corporation|HOT STAMPED STEEL AND METHOD FOR HOT STAMPED PRODUCTION|
    CN104040010B|2012-01-13|2016-06-15|新日铁住金株式会社|The manufacture method of cold-rolled steel sheet and cold-rolled steel sheet|
    BR112015002312A2|2012-08-06|2017-07-04|Nippon Steel & Sumitomo Metal Corp|cold-rolled steel plate and method for producing it, and hot-formed element|
    CN105518171B|2013-09-10|2017-04-05|株式会社神户制钢所|The manufacture method of hot pressing steel plate and stamping product and stamping product|
    JP6225654B2|2013-11-14|2017-11-08|新日鐵住金株式会社|Hot stamping steel manufacturing method, hot stamping steel plate manufacturing method and hot stamping steel plate|
    KR101528067B1|2013-12-20|2015-06-10|주식회사 포스코|Steel for hot press forming with excellent formability and weldability, and mmehtod for manufacturing thereof|
    CA2934599C|2013-12-27|2019-01-22|Nippon Steel & Sumitomo Metal Corporation|Hot-pressed steel sheet member, method of manufacturing the same, and steel sheet for hot pressing|
    KR101833655B1|2013-12-27|2018-02-28|신닛테츠스미킨 카부시키카이샤|Hot-pressed steel sheet member, production method for same, and steel sheet for hot pressing|
    TWI512116B|2014-01-02|2015-12-11|Nippon Steel & Sumitomo Metal Corp|A hot-pressed steel sheet member, a method for manufacturing the same, and a steel sheet for hot pressing|
    TWI513829B|2014-01-03|2015-12-21|Nippon Steel & Sumitomo Metal Corp|A hot-pressed steel sheet member, a method for manufacturing the same, and a steel sheet for hot pressing|
    CN105874091A|2014-01-06|2016-08-17|新日铁住金株式会社|Hot-formed member and process for manufacturing same|
    KR101821913B1|2014-01-06|2018-03-08|신닛테츠스미킨 카부시키카이샤|Steel material and process for producing same|
    BR112016018119B8|2014-02-05|2020-12-15|Arcelormittal S A|steel plate, method for producing a steel plate and use of a steel plate|
    JP6119655B2|2014-03-31|2017-04-26|Ｊｆｅスチール株式会社|High strength alloyed hot dip galvanized steel strip excellent in formability with small material variations in steel strip and method for producing the same|
    JP2015196890A|2014-04-02|2015-11-09|本田技研工業株式会社|Hot stamp molded body|
    KR101672103B1|2014-12-22|2016-11-02|주식회사 포스코|Hot rolled steel sheet for hot galvanized iron having high surface quality and high strength, and method for producing the same|
    KR101672102B1|2014-12-22|2016-11-02|주식회사 포스코|Hot rolled steel sheet for hot galvanized iron having high surface quality and high strength, and method for producing the same|
    KR101677351B1|2014-12-26|2016-11-18|주식회사 포스코|Hot rolled steel sheet for hot press forming having low deviation of mechanical property and excellent formability and corrosion resistance, hot pressed part using the same and method for manufacturing thereof|
    CN104762460B|2015-03-12|2017-01-11|燕山大学|Rolling and deep-processing short-process integrated manufacturing method of high-strength steel automobile sheet|
    KR101736620B1|2015-12-15|2017-05-17|주식회사 포스코|Ultra-high strength steel sheet having excellent phosphatability and hole expansibility, and method for manufacturing the same|
    CN107127238B|2016-02-26|2019-12-27|宝山钢铁股份有限公司|Hot stamping forming method for zinc-based plated steel plate or steel strip|
    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|
    US10619223B2|2016-04-28|2020-04-14|GM Global Technology Operations LLC|Zinc-coated hot formed steel component with tailored property|
    US10288159B2|2016-05-13|2019-05-14|GM Global Technology Operations LLC|Integrated clutch systems for torque converters of vehicle powertrains|
    KR20180011004A|2016-07-22|2018-01-31|현대제철 주식회사|Steel for hot stamping molding, manufacturing method for steel for hot stamping molding, hot stamping product and manufacturing method for hot stamping product|
    US11136643B2|2016-08-10|2021-10-05|Jfe Steel Corporation|High-strength steel sheet and method for producing same|
    US10240224B2|2016-08-12|2019-03-26|GM Global Technology Operations LLC|Steel alloy with tailored hardenability|
    BR112019001901A2|2016-08-16|2019-05-07|Nippon Steel & Sumitomo Metal Corporation|hot formed part|
    US10907235B2|2016-09-13|2021-02-02|Nippon Steel Corporation|Steel sheet|
    WO2018067554A1|2016-10-03|2018-04-12|Ak Steel Properties, Inc.|High elongation press hardened steel manufacture of the same|
    RU2630084C1|2016-12-02|2017-09-05|Федеральное Государственное Унитарное Предприятие "Центральный научно-исследовательский институт черной металлургии им. И.П. Бардина" |Method for production of cold-rolling steel sheet products with hot forming|
    RU2630082C1|2016-12-02|2017-09-05|Федеральное Государственное Унитарное Предприятие "Центральный научно-исследовательский институт черной металлургии им. И.П. Бардина" |Method for production of hot-rolling steel sheet products with hot forming|
    US10260121B2|2017-02-07|2019-04-16|GM Global Technology Operations LLC|Increasing steel impact toughness|
    KR101949027B1|2017-07-07|2019-02-18|주식회사 포스코|Ultra-high strength hot-rolled steel sheet and method for manufacturing the same|
    CN110760765B|2018-07-27|2021-03-12|宝山钢铁股份有限公司|600 MPa-grade quenched and tempered steel plate with ultralow cost, high elongation and strain aging embrittlement resistance and manufacturing method thereof|
    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|
    WO2020245626A1|2019-06-03|2020-12-10|Arcelormittal|Cold rolled and coated steel sheet and a method of manufacturing thereof|
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    法律状态:
    2018-03-13| B06T| Formal requirements before examination [chapter 6.20 patent gazette]|
    2018-09-11| B07A| Application suspended after technical examination (opinion) [chapter 7.1 patent gazette]|
    2019-02-26| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2019-04-24| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 11/01/2013, OBSERVADAS AS CONDICOES LEGAIS. (CO) 20 (VINTE) ANOS CONTADOS A PARTIR DE 11/01/2013, OBSERVADAS AS CONDICOES LEGAIS |
    2019-11-19| B25D| Requested change of name of applicant approved|Owner name: NIPPON STEEL CORPORATION (JP) |
    2021-11-03| B21F| Lapse acc. art. 78, item iv - on non-payment of the annual fees in time|Free format text: REFERENTE A 9A ANUIDADE. |
    2022-02-22| 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 2652 DE 03-11-2021 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
    JP2012004550|2012-01-13|
    JP2012-004550|2012-01-13|
    PCT/JP2013/050385|WO2013105633A1|2012-01-13|2013-01-11|Hot stamp molded article, and method for producing hot stamp molded article|
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