Hot stamped component

Abstract

This hot stamped component has a predetermined chemical composition, in a position at ¼ of a sheet thickness from a surface, in a texture of prior austenite, a maximum value of pole densities of an orientation group expressed by Euler angles of Φ=60° to 90°, φ1=60° to 90°, and φ2=45° is 3.0 or more, an average value of block sizes of martensite, tempered martensite and bainite is 1.20 μm or less.

Description

TECHNICAL FIELD OF INVENTION

[0001] The present invention relates to a hot stamped component.

[0002] Priority is claimed on Japanese Patent Application No. 2022-090847, filed Jun. 3, 2022, the content of which is incorporated herein by reference.BACKGROUND ART

[0003] In recent years, there has been a demand for a reduction in a weight of a vehicle body for a vehicle from the perspective of environmental protection and resource saving, and a high-strength steel sheet has been applied to vehicle members. Vehicle members are manufactured by press forming, but not only a forming load is increased but also the formability deteriorates as the strength of a steel sheet is increased. For this reason, the formability of a high-strength steel sheet into a member having a complicated shape becomes an issue.

[0004] In order to solve this issue, the application of a hot stamping technique in which press forming is performed after a steel sheet is heated up to a high temperature of an austenite range where the steel sheet softens is in progress. Hot stamping is attracting attention as a technique that achieves both the formability of a steel sheet into a vehicle member and strength of a vehicle member by performing hardening of the steel sheet in a die at the same time as press working.

[0005] For example, Patent Document 1 discloses a hardenable steel having excellent cold formability that can obtain excellent impact strength and hardness by reheating and quenching the steel.PRIOR ART DOCUMENTPatent DocumentPatent Document 1

[0006] Japanese Unexamined Patent Application Publication No. 2020-508393Non-Patent DocumentNon-Patent Document 1

[0007] Acta Materialia, 58 (2010), 6393-6403DISCLOSURE OF INVENTIONProblems to be Solved by Invention

[0008] When a hot stamped component with further improved tensile strength is used as a vehicle member, a greater effect of vehicle weight reduction can be achieved. However, since it is a vehicle member, it may be subjected to bending deformation due to a collision or the like, and therefore the hot stamped component needs to have high bendability. However, Patent Document 1 does not consider bendability.

[0009] The present invention has been made in view of the above-mentioned problem, and an object of the present invention is to provide a hot stamped component having high strength and excellent bendability.Means for Solving the Problem

[0010] The gist of the present invention is as follows.

[0011] [1]A hot stamped component according to an aspect of the present invention comprising, as a chemical composition, by mass %:

[0012] C: 0.40% to 0.70%;

[0013] Si: 0.010% to 3.000%;

[0014] Mn: 0.10% or more and less than 0.60%;

[0015] P: 0.100% or less;

[0016] S: 0.0100% or less;

[0017] N: 0.0100% or less;

[0018] O: 0.0200% or less;

[0019] Al: 0.0010% to 0.5000%;

[0020] Nb: 0.0010% to 0.1000%;

[0021] Ti: 0.010% to 0.100%;

[0022] Cr: 0.010% to 1.000%;

[0023] Mo: 0.050% to 1.000%;

[0024] B: 0.0005% to 0.0100%;

[0025] Co: 0% to 3.00%;

[0026] Ni: 0% to 3.00%;

[0027] Cu: 0% to 3.00%;

[0028] V: 0% to 3.00%;

[0029] W: 0% to 3.00%;

[0030] Ca: 0% to 0.1000%;

[0031] Mg: 0% to 1.0000%;

[0032] REM: 0% to 1.0000%;

[0033] Sb: 0% to 1.000%;

[0034] Sn: 0% to 1.000%;

[0035] Zr: 0% to 1.000%;

[0036] As: 0% to 0.100%; and

[0037] a remainder: Fe and impurities,

[0038] in a position at ¼ of a sheet thickness from a surface,

[0039] in a texture of prior austenite, a maximum value of pole densities of an orientation group expressed by Euler angles of Φ=60° to 90°, φ1=60° to 90°, and φ2=45° is 3.0 or more,

[0040] an average value of block sizes of martensite, tempered martensite and bainite is 1.20 μm or less.

[0041] [2] The hot stamped component according to [1] may comprise, as the chemical composition, by mass %, one or more selected from the group consisting of:

[0042] Co: 0.01% to 3.00%;

[0043] Ni: 0.01% to 3.00%;

[0044] Cu: 0.01% to 3.00%;

[0045] V: 0.01% to 3.00%;

[0046] W: 0.01% to 3.00%;

[0047] Ca: 0.0001% to 0.1000%;

[0048] Mg: 0.0001% to 1.0000%;

[0049] REM: 0.0001% to 1.0000%;

[0050] Sb: 0.001% to 1.000%;

[0051] Sn: 0.001% to 1.000%;

[0052] Zr: 0.001% to 1.000%; and

[0053] As: 0.001% to 0.100%.Effects of Invention

[0054] According to the above-described aspects of the present invention, it is possible to provide a hot stamped component having high strength and excellent bendability.EMBODIMENTS OF INVENTION

[0055] The present inventors found that by controlling a texture of prior austenite and an average value of block sizes of martensite, tempered martensite and bainite in a position at ¼ of a sheet thickness from a surface of a hot stamped component, the bendability of the hot stamped component can be improved. In particularly, the present inventors found that the bendability of a hot stamped component can be improved by controlling not a texture of martensite, tempered martensite, bainite, or the like, which are a microstructure of the hot stamped component but a texture of prior austenite before transformation to martensite, bainite, or the like (i.e., state of austenite at a high temperature of Ar3 point or higher) to be within a specific range.

[0056] In addition, the present inventors found that in order to obtain the hot stamped component having the above features, it is particularly effective to strictly control final rolling conditions during hot rolling.

[0057] Hereinafter, the hot stamped component according to the present embodiment will be described in detail. First, the reason the chemical composition of the hot stamped component according to the present embodiment is limited will be described.

[0058] A limited numerical range described using “to” described below includes a lower limit and an upper limit. Numerical values represented using “less than” or “more than” are not included in a numerical range. All percentages (%) related to the chemical composition mean mass %.

[0059] The hot stamped component according to the present embodiment comprises, as a chemical composition, by mass %, C: 0.40% to 0.70%, Si: 0.010% to 3.000%, Mn: 0.10% or more and less than 0.60%, P: 0.100% or less, S: 0.0100% or less, N: 0.0100% or less, O: 0.0200% or less, Al: 0.0010% to 0.5000%, Nb: 0.0010% to 0.1000%, Ti: 0.010% to 0.100%, Cr: 0.010% to 1.000%, Mo: 0.050% to 1.000%, B: 0.0005% to 0.0100%, and a remainder: Fe and impurities.

[0060] Each element will be described below.C: 0.40% to 0.70%

[0061] C is an element that improves the strength of the hot stamped component. When the C content is less than 0.40%, a desired strength of the hot stamped component cannot be obtained. For this reason, the C content is set to 0.40% or more. The C content is preferably more than 0.40%, 0.42% or more or 0.44% or more.

[0062] On the other hand, when the C content is more than 0.70%, the strength excessively increases and the bendability of the hot stamped component deteriorates. For this reason, the C content is set to 0.70% or less. The C content is preferably 0.65% or less or 0.60% or less.Si: 0.010% to 3.000%

[0063] Si is an element that improves the strength of the hot stamped component by solid-solution strengthening. When the Si content is less than 0.010%, a desired strength of the hot stamped component cannot be obtained. For this reason, the Si content is set to 0.010% or more. The Si content is preferably 0.100% or more, 0.300% or more or 0.500% or more.

[0064] On the other hand, when the Si content is more than 3.000%, the amount of ferrite increases and a desired strength of the hot stamped component cannot be obtained. For this reason, the Si content is set to 3.000% or less. The Si content is preferably 2.000% or less, 1.000% or less or 0.800% or less.Mn: 0.10% or More and Less than 0.60%

[0065] Mn is an element that increases hardenability of steel and increases the strength of the hot stamped component. When the Mn content is less than 0.10%, a desired strength of the hot stamped component cannot be obtained. For this reason, the Mn content is set to 0.10% or more. The Mn content is preferably 0.20% or more or 0.35% or more.

[0066] On the other hand, when the Mn content is 0.60% or more, a desired texture of prior austenite cannot be obtained. For this reason, the Mn content is set to less than 0.60%. The Mn content is preferably 0.55% or less or 0.50% or less.P: 0.100% or Less

[0067] P decreases the strength of the grain boundaries by segregating in the grain boundaries. As a result, P deteriorates the bendability of the hot stamped component. When the P content is more than 0.100%, the bendability of the hot stamped component deteriorates significantly. For this reason, the P content is set to 0.100% or less. The P content is preferably 0.050% or less or 0.010% or less.

[0068] The lower limit of the P content may be 0%. However, when the P content is reduced to less than 0.0001%, the dephosphorization cost increases significantly, which is not preferable economically. For this reason, the P content may be set to 0.0001% or more.S: 0.0100% or Less

[0069] S forms inclusions in steel. When the S content is more than 0.0100%, the bendability of the hot stamped component deteriorates significantly. For this reason, the S content is set to 0.0100% or less. The S content is preferably 0.0080% or less, 0.0050% or less or 0.0030% or less.

[0070] The lower limit of the S content may be 0%. However, when the S content is reduced to less than 0.0001%, the desulfurization cost increases significantly, which is not preferable economically. For this reason, the S content may be set to 0.0001% or more.N: 0.0100% or Less

[0071] N forms nitrides in steel. When the N content is more than 0.0100%, the bendability of the hot stamped component deteriorates significantly. For this reason, the N content is set to 0.0100% or less. The N content is preferably 0.0080% or less, 0.0060% or less or 0.0040% or less.

[0072] The lower limit of the N content may be 0%. However, when the N content is reduced to less than 0.0001%, the denitrification cost increases significantly, which is not preferable economically. For this reason, the N content may be set to 0.0001% or more.O: 0.0200% or Less

[0073] O forms coarse oxides when a large amount of O is comprised in steel. When the O content is more than 0.0200%, the bendability of the hot stamped component deteriorates significantly. For this reason, the O content is set to 0.0200% or less. The O content is preferably 0.0100% or less, 0.0070% or less, 0.0040% or less or 0.0030% or less.

[0074] The O content may be 0%. However, in order to disperse many oxides during deoxidizing of molten steel, the O content may be set to 0.0005% or more.Al: 0.0010% to 0.5000%

[0075] Al is an element having an effect of deoxidizing molten steel and achieving soundness of the steel (minimizing the occurrence of defects such as blowholes in steel). When the Al content is less than 0.0010%, deoxidation is not sufficiently performed, and coarse oxides are generated. As a result, the bendability of the hot stamped component deteriorates. For these reasons, the Al content is set to 0.0010% or more. The Al content is preferably 0.0050% or more, 0.0100% or more or 0.0300% or more.

[0076] On the other hand, when the Al content is more than 0.5000%, coarse oxides are generated in steel. As a result, the bendability of the hot stamped component deteriorates significantly. For this reason, the Al content is set to 0.5000% or less. The Al content is preferably 0.4000% or less, 0.3000% or less, or 0.2000% or less or 0.1000% or less.Nb: 0.0010% to 0.1000%

[0077] Nb is an element that forms carbonitrides in steel and improves the strength of the hot stamped component by precipitation strengthening. When the Nb content is less than 0.0010%, a desired strength of the hot stamped component cannot be obtained. For this reason, the Nb content is set to 0.0010% or more. The Nb content is preferably 0.0050% or more, 0.0100% or more or 0.0200% or more.

[0078] On the other hand, when the Nb content is more than 0.1000%, many carbonitrides are generated in steel, and the bendability of the hot stamped component deteriorates. For this reason, the Nb content is set to 0.1000% or less. The Nb content is preferably 0.0800% or less or 0.0600% or less.Ti: 0.010% to 0.100%

[0079] Ti is an element that forms carbonitrides in steel and improves the strength of the hot stamped component by precipitation strengthening. When the Ti content is less than 0.010%, a desired strength of the hot stamped component cannot be obtained. For this reason, the Ti content is set to 0.010% or more. The Ti content is preferably 0.020% or more or 0.025% or more.

[0080] On the other hand, when the Ti content is more than 0.100%, many carbonitrides are generated in steel, and the bendability of the hot stamped component deteriorates. For this reason, the Ti content is set to 0.100% or less. The Ti content is preferably 0.080% or less, 0.060% or less or 0.050% or less.Cr: 0.010% to 1.000%

[0081] Cr is an element that increases the strength of the hot stamped component by dissolving in prior austenite grains during heating before hot stamping. When the Cr content is less than 0.010%, a desired strength of the hot stamped component cannot be obtained. For this reason, the Cr content is set to 0.010% or more. The Cr content is preferably 0.100% or more, 0.150% or more or 0.200% or more.

[0082] On the other hand, when the Cr content is more than 1.000%, a desired texture of prior austenite cannot be obtained. For this reason, the Cr content is set to 1.000% or less. The Cr content is preferably 0.700% or less, 0.500% or less or 0.400% or less.Mo: 0.050% to 1.000%

[0083] Mo is an element that increases the strength of the hot stamped component by dissolving in prior austenite grains during heating before hot stamping. When the Mo content is less than 0.050%, a desired strength of the hot stamped component cannot be obtained. For this reason, the Mo content is set to 0.050% or more. The Mo content is preferably 0.100% or more or 0.150% or more.

[0084] On the other hand, when the Mo content is more than 1.000%, a desired texture of prior austenite cannot be obtained. For this reason, the Mo content is set to 1.000% or less. The Mo content is preferably 0.800% or less, 0.600% or less or 0.400% or less.B: 0.0005% to 0.0100%

[0085] B is an element that improves the hardenability of steel. When the B content is less than 0.0005%, a desired strength of the hot stamped component cannot be obtained. For this reason, the B content is set to 0.0005% or more. The B content is preferably 0.0020% or more or 0.0030% or more.

[0086] On the other hand, when the B content is more than 0.0100%, coarse intermetallic compounds are formed in the hot stamped component. As a result, the bendability of the hot stamped component deteriorates. For this reason, the B content is set to 0.0100% or less. The B content is preferably 0.0080% or less, 0.0060% or less or 0.0040% or less.

[0087] The hot stamped component may comprise the following elements as optional elements in place of a part of Fe. The content of the following optional elements obtained when the following optional elements are not contained is 0%.Co: 0.01% to 3.00%

[0088] Co is an element that improves strength of the hot stamped component by solid-solution strengthening. In order to reliably obtain the effect, the Co content is preferably set to 0.01% or more, and more preferably set to 0.05% or more.

[0089] On the other hand, since the above effect will be saturated even if a large amount is comprised, the Co content is set to 3.00% or less. If necessary, the Co content may be limited to 2.00% or less, 1.50% or less, 1.00% or less or 0.50% or less.Ni: 0.01% to 3.00%

[0090] Ni has an effect of increasing strength of the hot stamped component by dissolving in prior austenite grains during heating before hot stamping. In order to reliably obtain the effect, the Ni content is preferably set to 0.01% or more.

[0091] On the other hand, since the above effect will be saturated even if a large amount is comprised, the Ni content is set to 3.00% or less. If necessary, the Ni content may be limited to 2.00% or less, 1.50% or less, 1.00% or less or 0.50% or less.Cu: 0.01% to 3.00%

[0092] Cu has an effect that increases the strength of the hot stamped component by dissolving in prior austenite grains during heating before hot stamping. In order to reliably obtain the effect, the Cu content is preferably set to 0.01% or more, and more preferably set to 0.05% or more.

[0093] On the other hand, since the above effect will be saturated even if a large amount is comprised, the Cu content is set to 3.00% or less. If necessary, the Cu content may be limited to 2.00% or less, 1.50% or less, 1.00% or less or 0.50% or less.V: 0.01% to 3.00%

[0094] V has an effect that forms carbonitrides in steel and improves the strength of the hot stamped component by precipitation strengthening. In order to reliably obtain the effect, the V content is preferably set to 0.01% or more, and more preferably set to 0.05% or more.

[0095] On the other hand, when the V content is more than 3.00%, a lot of coarse carbonitrides is generated in steel. As a result, the bendability of the hot stamped component deteriorates. For this reason, the V content is set to 3.00% or less. If necessary, the V content may be limited to 2.00% or less, 1.50% or less, 1.00% or less or 0.50% or less.W: 0.01% to 3.00%

[0096] W has an effect of improving the strength of the hot stamped component. In order to reliably obtain the effects, the W content is preferably set to 0.01% or more, and more preferably set to 0.05% or more.

[0097] On the other hand, since the above effect will be saturated even if a large amount is comprised, the W content is set to 3.00% or less. If necessary, the W content may be limited to 2.00% or less, 1.50% or less, 1.00% or less or 0.50% or less.Ca: 0.0001% to 0.1000%

[0098] Ca is an element that suppresses generation of carbides that become starting points for fracture, and contributes for improvement of the bendability of the hot stamped component. In order to reliably obtain the effect, the Ca content is preferably set to 0.0001% or more, and more preferably set to 0.0010% or more.

[0099] On the other hand, since the above effect will be saturated even if a large amount is comprised, the Ca content is set to 0.1000% or less. If necessary, the Ca content may be limited to 0.0500% or less, 0.0200% or less, 0.0100% or less or 0.0060% or less.Mg: 0.0001% to 1.0000%

[0100] Mg refines the microstructure due to formation of oxides and sulfides in molten steel, suppressing formation of a coarse MnS, and dispersing a lot of fine oxides. As a result, Mg contributes for improvement of the bendability of the hot stamped component. In order to reliably obtain these effects, the Mg content is preferably set to 0.0001% or more, and more preferably set to 0.0010% or more.

[0101] On the other hand, since the above effect will be saturated even if a large amount is comprised, the Mg content is set to 1.0000% or less. If necessary, the Mg content may be limited to 0.0500% or less, 0.0200% or less, 0.0100% or less or 0.0060% or less.REM: 0.0001% to 1.000%

[0102] REM suppresses generation of coarse oxides. As a result, REM contributes for improvement of the bendability of the hot stamped component. In order to reliably obtain the effect, the REM content is preferably set to 0.0001% or more, and more preferably set to 0.0010% or more.

[0103] On the other hand, since the above effect will be saturated even if a large amount is comprised, the REM content is set to 1.0000% or less. If necessary, the REM content may be limited to 0.0500% or less, 0.0200% or less, 0.0100% or less or 0.0060% or less.

[0104] In the present embodiment, REM refers to a total of 17 elements that are composed of Sc, Y and lanthanoid, and the REM content refers to the total content of these elements.Sb: 0.001% to 1.000%

[0105] Sb suppresses generation of coarse oxides. As a result, Sb contributes for improvement of the bendability of the hot stamped component. In order to reliably obtain the effect, the Sb content is preferably set to 0.001% or more.

[0106] On the other hand, since the above effect will be saturated even if a large amount is comprised, the Sb content is set to 1.000% or less. If necessary, the Sb content may be limited to 0.500% or less, 0.200% or less, 0.100% or less or 0.050% or less.Sn: 0.001% to 1.000%

[0107] Sn suppresses generation of coarse oxides. As a result, Sn contributes for improvement of the bendability of the hot stamped component. In order to reliably obtain the effect, the Sn content is preferably set to 0.001% or more.

[0108] On the other hand, since the above effect will be saturated even if a large amount is comprised, the Sn content is set to 1.000% or less. If necessary, the Sn content may be limited to 0.500% or less, 0.200% or less, 0.100% or less or 0.050% or less.Zr: 0.001% to 1.000%

[0109] Zr suppresses generation of coarse oxides. As a result, Zr contributes for improvement of the bendability of the hot stamped component. In order to reliably obtain the effect, the Zr content is preferably set to 0.001% or more.

[0110] On the other hand, since the above effect will be saturated even if a large amount is comprised, the Zr content is set to 1.000% or less. If necessary, the Zr content may be limited to 0.500% or less, 0.200% or less, 0.100% or less or 0.050% or less.As: 0.001% to 0.100%

[0111] As refines the prior austenite grains by lowering an austenite single-phase transformation temperature. As a result, As contributes for improvement of the bendability of the hot stamped component. In order to reliably obtain the effect, the As content is preferably set to 0.001% or more.

[0112] On the other hand, since the above effect will be saturated even if a large amount is comprised, the As content is set to 0.100% or less. If necessary, the As content may be limited to 0.500% or less, 0.200% or less, 0.100% or less or 0.050% or less.

[0113] The remainder of the chemical composition of the hot stamped component may be Fe and impurities. Elements which are unavoidably mixed from a steel raw material or scrap and / or during the manufacture of steel and are allowed in a range where the properties of the hot stamped component according to the present embodiment do not deteriorate are exemplary examples of the impurities.

[0114] The above-mentioned chemical composition of the hot stamped component may be measured by an ordinary analysis method. For example, the chemical composition may be measured using inductively coupled plasma-atomic emission spectrometry (ICP-AES). C and S may be measured using a combustion-infrared absorption method, N may be measured using an inert gas fusion-thermal conductivity method, and O may be measured using an inert gas fusion-nondispersive infrared absorption method.

[0115] When a plating layer or a coating film is provided on the surface of the hot stamped component, the chemical composition is analyzed after the plating layer or the coating film is removed by mechanical grinding.

[0116] Next, the microstructure of the hot stamped component according to the present embodiment will be described.

[0117] In the hot stamped component according to the present embodiment, in a position at ¼ of a sheet thickness from a surface, in a texture of prior austenite, a maximum value of pole densities of an orientation group expressed by Euler angles of Φ=60° to 90°, φ1=60° to 90°, and φ2=450 is 3.0 or more, an average value of block sizes of martensite, tempered martensite and bainite is 1.20 μm or less.

[0118] In the present embodiment, the microstructure is specified in the position at ¼ of the sheet thickness from the surface of the hot stamped component (in a region from a depth of ⅛ of the sheet thickness from the surface to a depth of ⅜ of the sheet thickness from the surface). The reason therefor is that the microstructure at this position indicates a typical microstructure of the hot stamped component.

[0119] Note that when the hot stamped component has the plating layer or the coating film on the surface thereof, the “surface” refers to the interface of the plating layer or the coating film and the base steel sheet.

[0120] In texture of prior austenite, maximum value of pole densities of orientation group expressed by Euler angles of Φ=60° to 90°, φ1=60° to 90°, and φ2=45°: 3.0 or more

[0121] The present inventors obtained the following findings about a texture of prior austenite.

[0122] By developing the texture of prior austenite, it is possible to alleviate a strain concentration introduced by bending deformation. As a result, an increase of a load in an initial stage of the bending deformation is reduced and the bendability of the hot stamped component can be increased.

[0123] In the texture of prior austenite, when the maximum value of pole densities of the orientation group expressed by Euler angles of Φ=60° to 90°, φ1=60° to 90°, and φ2=45° (hereinafter, it may be referred as the pole density in the texture of prior austenite) is less than 3.0, a desired bendability of the hot stamped component cannot be obtained. For this reason, the maximum value of the pole densities of the orientation group in the texture of prior austenite is set to 3.0 or more. It is preferably 5.0 or more.

[0124] The upper limit is not particularly limited, but the maximum value of the pole densities of the orientation group in the texture of prior austenite may be set to 50.0 or less, 20.0 or less, 15.0 or less or 10.0 or less.

[0125] The pole density in the texture of prior austenite is measured by the following method.

[0126] The pole density of the texture of prior austenite is measured using an EBSD analyzer including a thermal field emission type scanning electron microscope and an EBSD detector, and the software “OIM Analysis (registered trademark)” attached to the EBSD analyzer. The pole density of the texture of prior austenite can be obtained by using the orientation data measured by the EBSD (Electron Back Scattering Diffraction) method and an orientation distribution function (ODF) that displays the three-dimensional texture calculated by computing, using spherical harmonics.

[0127] For a sample to be subjected to analysis by the EBSD method, a cross section parallel to a rolling direction and perpendicular to a sheet surface is mechanically polished, and strain is removed by chemical polishing or electrolytic polishing. Using this sample, EBSD measurement is performed at the position at ¼ of the sheet thickness from the surface (in the region from the depth of ⅛ of the sheet thickness from the surface to the depth of ⅜ of the sheet thickness from the surface), with a measurement range of 150 μm in length and a region of 50 μm in the sheet thickness direction and measurement intervals of 0.2 μm. For the measurement, an EBSD analyzer including a thermal field emission type scanning electron microscope and an EBSD detector may be used, for example, an EBSD analyzer including JSM-7001F manufactured by JEOL Ltd. and DVC5-type detector manufactured by TSL Solutions may be used. In this case, the degree of vacuum in the EBSD analyzer may be set to 9.6×10−5 Pa or less, the acceleration voltage may be set to 15 kV and the irradiation current level may be set to 13.

[0128] The orientation of prior austenite is measured by the following method. The orientation of prior austenite is calculated by the method described in Non-Patent Document 1, and the orientation of the prior austenite in each coordinate of the EBSD-measured region is specified. Next, an orientation map of prior austenite is created using the “Inverse Pole Figure” function installed in the software “OIM Analysis (registered trademark)” attached to the EBSD analyzer. Based on the orientation map, the maximum value of pole densitis of an orientation group within the ranges of Φ=60° to 90°, φ1=60° to 90° in section of φ2=45° is calculated. As a result, the maximum value of the pole densitis of the orientation group expressed by Euler angles of 0=60° to 90°, φ1=60° to 90°, and φ2=450 is obtained.

[0129] Analyses of a texture using the Euler angles (φ1, Φ, φ2) are widely performed. For example, the definition of the Euler angles (φ1, Φ, φ2) is described in Hiroshi Inoue: “Lecture (Easy Material Analysis Techniques)—Three-dimensional Orientation Analysis of Texture”, Light Metals, Vol. 41, No. 6 (1992), 358. By performing analysis using the above-mentioned software, even a person who does not fully understand the definition of the Euler angles (φ1, Φ, φ2) can easily calculate the maximum value of the pole densitis of the orientation group within the ranges of Φ=60° to 90°, φ1=60° to 90° in section of φ2=45°.

[0130] Average value of block sizes of martensite, tempered martensite and bainite: 1.20 μm or less

[0131] When the average value of block sizes of martensite, tempered martensite and bainite is more than 1.20 μm, a desired bendability of the hot stamped component cannot be obtained. For this reason, the average value of block sizes of martensite, tempered martensite and bainite is set to 1.20 μm or less. It is preferably 1.00 μm or less, and more preferably 0.90 μm or less.

[0132] The lower limit is not particularly limited, but it may be set to 0.30 μm or more, 0.40 μm or more or 0.50 μm or more.

[0133] The average value of block sizes of martensite, tempered martensite and bainite is measured by the following method.

[0134] A sample is cut out from an arbitrary position away from an end surface of the hot stamped component by a distance of 50 mm or more (a position that possibly avoids an end portion in a case where the sample cannot be collected at this position) so that a sheet thickness cross section parallel to the rolling direction can be observed. The size of the sample depends on a measurement device, but is set to a size that can be observed by at least about 10 mm in the rolling direction.

[0135] After polishing the cross section of the above sample using silicon carbide paper of #600 to #1500, the cross section is mirror-finished using liquid in which diamond powder having a grain size in the range of 1 to 6 μm is dispersed in a diluted solution of alcohol or the like or pure water. Next, the observation surface is finished by electrolytic polishing. Using this sample, in a position at ¼ of the sheet thickness from the surface (a region from a depth of ⅛ of the sheet thickness from the surface to a depth of ⅜ of the sheet thickness from the surface), an orientation information is obtained by measurement using an electron backscatter diffraction method with a measurement range of 150 μm in length and a region of 50 μm in the sheet thickness direction and measurement intervals of 0.2 μm. For the measurement, an EBSD analyzer including a thermal field emission type scanning electron microscope and an EBSD detector may be used, for example, an EBSD analyzer including JSM-7001F manufactured by JEOL Ltd. and DVC5-type detector manufactured by TSL Solutions may be used. In this case, the degree of vacuum in the EBSD analyzer may be set to 9.6×10−5 Pa or less, the acceleration voltage may be set to 15 kV and the irradiation current level may be set to 13.

[0136] In the obtained orientation information, using “Phase Map” function installed in the software “OIM Analysis (registered trademark)” attached to the EBSD analyzer, a region where a crystal structure is fcc is extracted. In these regions, using “Grain Average Misorientation” function installed in the software “OIM Analysis (registered trademark)” attached to the EBSD analyzer, under the condition that boundary with a crystal misorientation of 5° or more is regarded as the grain boundary, regions where the grain average misorientation is more than 0.5° are extracted as martensite, tempered martensite and bainite. For the obtained region, under the condition that boundary with a crystal misorientation of 150 or more is regarded as the grain boundary, the average value of block sizes of martensite, tempered martensite and bainite is obtained by obtaining the value calculated by the Number method using the “Grain Size (diameter)” function.

[0137] Note that the rolling direction of the hot stamped component is determined by the following method.

[0138] First, a sample is collected so that a sheet thickness cross section of the hot stamped component can be observed. The sheet thickness cross section of the collected sample is finished by mirror polishing, and then observed with an optical microscope. The observation area is width of 500 μm and full of the sheet thickness, and the areas with low brightness are determined as inclusions. Next, using the sheet thickness cross section initially observed by the above method as a reference, in the range of 0° to 180° with the sheet thickness direction as the axis, the cross-sectional observations of the plane parallel to the plane rotated in 5° increments are performed in the same way as the above method. The average values of the lengths of the long axes of inclusions in each cross section are calculated respectively, and a direction parallel to the long axes of the inclusions in the cross section in which the average value of the length of the long axes of the inclusions is maximum is determined as the rolling direction.

[0139] Note that when the rolling direction of the hot stamped component is known in advance, the rolling direction of the hot stamped component may be determined without using the above-mentioned determination method.

[0140] The microstructure of the hot stamped component is not particularly limited as long as a desired strength and bendability can be obtained. For example, the microstructure may consist of, by area %, a total of 90% or more of martensite, bainite and tempered martensite, and 10% or less of ferrite and residual austenite.

[0141] The area ratios of each structure are measured by the following method.

[0142] A sample is cut out from an arbitrary position away from an end surface of the hot stamped component by a distance of 50 mm or more (a position that possibly avoids an end portion in a case where a sample cannot be collected at this position) so that a sheet thickness cross section parallel to the rolling direction can be observed. The size of the sample depends on a measurement device, but is set to a size that can be observed by at least about 10 mm in the rolling direction.

[0143] After polishing the cross section of the sample using silicon carbide paper of #600 to #1500, the cross section is mirror-finished using liquid in which diamond powder having a grain size in the range of 1 to 6 μm is dispersed in a diluted solution of alcohol or the like or pure water. Next, the observation surface is finished by electrolytic polishing. At an arbitrary position on the cross section of the sample in a longitudinal direction, for a region which has a length of 50 μm and is present in a region from the depth of ⅛ of the sheet thickness from the surface to the depth of ⅜ of the sheet thickness from the surface, an orientation information is obtained by measurement using the electron backscatter diffraction method with measurement intervals of 0.1 μm. For the measurement, an EBSD analyzer including a thermal field emission type scanning electron microscope and an EBSD detector may be used, for example, an EBSD analyzer including JSM-7001F manufactured by JEOL Ltd. and DVC5-type detector manufactured by TSL Solutions may be used. In this case, a degree of vacuum in the EBSD analyzer may be set to 9.6×10−5 Pa or less, the acceleration voltage may be set to 15 kV and the irradiation current level may be set to 13.

[0144] Using the obtained crystal structure information and the “Phase Map” function installed in the software “OIM Analysis (registered trademark)” attached to the EBSD analyzer, a region where a crystal structure is fcc is determined as residual austenite. The ratio of the residual austenite is calculated, thereby obtaining the area ratio of the residual austenite. Next, in the regions where the crystal structure is bcc is determined as bainite, tempered martensite, martensite and ferrite. For these regions, using the “Grain Average Misorientation” function installed in the software “OM Analysis (registered trademark)” attached to the EBSD analyzer, under the condition that boundary with a crystal misorientation of 5° or more is regarded as the grain boundary, regions where the grain average misorientation is 0.50 or less are extracted as ferrite. The area ratio of the extracted ferrite is calculated, thereby obtaining the area ratio of ferrite.

[0145] Subsequently, the area ratio of the remaining region (the region where “Grain Average Misorientation” is more than 0.5°) is regarded as the area ratio as martensite, tempered martensite and bainite.

[0146] The hot stamped component may have a plating layer or a coating film on the surface. By having the plating layer or the coating film on the surface, corrosion resistance can be improved after hot stamping. Examples of the plating layer include an aluminum plating layer, aluminum-galvanized layer, aluminum-silicon plating layer, hot-dip galvanized layer, electrogalvanized layer, galvannealed layer, zinc-nickel plating layer, aluminum-magnesium-zinc-based plating layer.

[0147] The sheet thickness of the hot stamped component according to the present embodiment is not particularly limited, but it is preferably set to 0.5 to 3.5 mm from the perspective of reducing the weight of a vehicle body or the like.

[0148] It is not specifically necessary to limit the shape of the hot stamped component. For example, the hot stamped component may have a flat sheet shape, a curved shape, or a three-dimensional shape such as a hat shape.

[0149] The hot stamped component according to the present embodiment preferably have a tensile strength of 2300 MPa or more. The tensile strength is more preferably 2400 MPa or more, and even more preferably 2500 MPa or more. It is not necessary to limit the upper limit of the tensile strength, if necessary, the tensile strength may be set to 3000 MPa or less or 2800 MPa or less.

[0150] The tensile strength is obtained according to the test method described in JIS Z 2241:2011 by producing a No. 5 test piece described in JIS Z 2241:2011 from a flat position of the hot stamped component. A crosshead speed is set to 1 mm / min.

[0151] When the hot stamped component according to the present embodiment has a flat sheet shape (has no curved portion, etc.), a load at a ½ stroke of a stroke at the maximum load is preferably 8050 N or more. It is more preferably 8100 N or more, and even more preferably 8150 N or more. However, these standards are based on the case where the sheet thickness of the hot stamped component is 1.6 mm.

[0152] The load at the ½ stroke is obtained by performing a bending test under the following conditions based on the VDA standard (VDA238-100: 2017-04) specified by the Verband der Automobilindustrie and obtaining the load at the ½ stroke of the stroke at the maximum load.

[0153] When the sheet thickness of the hot stamped component is more than 1.6 mm, the bending test is performed after reducing the sheet thickness to 1.6 mm.

[0154] When the sheet thickness of the hot stamped component is less than 1.6 mm, where t is the sheet thickness of the hot stamped component, the load at the ½ stroke of the stroke at the maximum load is preferably 8050×t / 1.6 (N) or more.

[0155] Note that the load at the ½ stroke of the stroke at the maximum load (however, when the sheet thickness of the hot stamped component is less than 1.6 mm, the value obtained by multiplying the load at the ½ stroke by 1.6 / t (t is the sheet thickness in mm)) rarely exceeds 8500 N, 8300 N or 8200 N.

[0156] Dimensions of test piece: 60 mm (rolling direction)×30 mm (direction parallel to sheet width direction)

[0157] Bending ridge: direction parallel to sheet width direction

[0158] Test method: roll support and punch pressing

[0159] Roll diameter: φ30 mm

[0160] Punch shape: tip end R=0.4 mm

[0161] Distance between rolls: 2.0×sheet thickness (mm)+0.5 mm

[0162] Pressing speed: 20 mm / min

[0163] Tester: for example, SHIMADZU AUTOGRAPH 20 kN

[0164] Next, a steel sheet for hot stamping for obtaining the hot stamped component according to the present embodiment will be described.

[0165] The steel sheet for hot stamping has the above-described chemical composition. The microstructure of the steel sheet for hot stamping is not particularly limited as long as a desired strength and bendability are obtained after hot stamping. For example, the microstructure may consist of, by area %, ferrite: 0% to 90%, bainite and martensite: 0% to 100%, pearlite: 0% to 80%, and residual austenite: 0% to 5%.

[0166] Further, the steel sheet for hot stamping may have a plating layer or a coating film on the surface. By having the plating layer or the coating film on the surface, corrosion resistance can be improved after hot stamping. Examples of the plating layer include an aluminum plating layer, aluminum-galvanized layer, aluminum-silicon plating layer, hot-dip galvanized layer, electrogalvanized layer, galvannealed layer, zinc-nickel plating layer, aluminum-magnesium-zinc-based plating layer.Manufacturing Method of Steel Sheet for Hot Stamping

[0167] A manufacturing method to obtain the steel sheet for hot stamping for obtaining the hot stamped component according to the present embodiment will be described. In order to obtain the above-described hot stamped component, it is particularly effective to control the finish rolling conditions during hot rolling in the manufacturing method of the steel sheet for hot stamping.Finish Rolling

[0168] In the finish rolling, it is preferable to perform a rolling at one stand before a final stand and a rolling at the final stand with a rolling reduction of 50% or more respectively. By performing the rolling at one stand before the final stand and the rolling at the final stand with the rolling reduction of 50% or more, it is possible to control prior austenite with a desired texture.

[0169] Note that the rolling reduction here can be expressed as (1−t1 / t0)×100(%), where t0 is an inlet sheet thickness and t1 is an outlet sheet thickness of each stand.

[0170] After the completion of the finish rolling (after the rolling of the final stand), it is preferable to start cooling after a lapse of 5.0 seconds or more. By elapsing 5.0 seconds or more before starting cooling, granular austenite grains can be generated. As a result, austenite grains with a flat shape are reduced, and granular austenite grains can be sufficiently secured.

[0171] Note that the cooling here does not include air cooling (cooling at an average cooling rate of slower than 10° C. / s), but includes, for example, such as water cooling at an average cooling rate of 10° C. / s or faster. The cooling stop temperature is preferably 550° C. to 650° C.

[0172] By the cooling after the finish rolling, austenite transforms into ferrite and pearlite. At this time, pearlite transformation progresses from the grain boundaries of the prior austenite grains. Pearlite having a specific texture is generated by transformation from austenite grains having a specific texture.

[0173] In addition, in order to soften the hot-rolled steel sheet, a coil after coiling may be subjected to softening heat treatment. The method of the softening heat treatment is not particularly limited, and an ordinary conditions may be used.

[0174] The total reduction during cold rolling is preferably set to 50% or less. The total reduction here can be expressed as (1−t3 / t2)×100(%), where t3 is the sheet thickness after the cold rolling and t2 is the sheet thickness before the cold rolling.Hot Stamping

[0175] A hot stamped component according to the present embodiment is obtained by hot stamping the steel sheet for hot stamping manufactured by the above-described method. As the hot stamping conditions, for example, it is preferable to heat the steel sheet for hot stamping to a temperature range of 800° C. to 1000° C. and hold in this temperature range for 60 to 1200 seconds.

[0176] By heating during hot stamping, a reverse transformation from pearlite to austenite is caused. Because pearlite has a specific texture, the texture of the austenite generated by the reverse transformation develops. By cooling after hot stamping, a transformation from austenite to martensite is caused. When the final structure becomes martensite, the texture of austenite is preserved. Therefore, the texture of the prior austenite remains developed in the structure after hot stamping.

[0177] When the heating temperature is lower than 800° C. or the holding time is shorter than 60 seconds, austenitization becomes insufficient, and the bendability may deteriorate or a desired strength may not be obtained in the hot stamped component. On the other hand, when the heating temperature is higher than 1000° C. or the holding time is longer than 1200 seconds, the grains of prior austenite grow excessively, and the bendability may deteriorate or a desired strength may not be obtained in the hot stamped component.

[0178] A heating atmosphere is, for example, such as the atmosphere, a gas combustion atmosphere with a controlled ratio of air and fuel, or a nitrogen atmosphere, and the dew point of these gases may be controlled.

[0179] After holding in the temperature range, hot stamping is performed. After hot stamping, cooling may be performed to a temperature range of 250° C. or lower at an average cooling rate of 20° C. / s or faster.

[0180] Examples of heating methods before hot stamping include heating using an electric furnace and a gas furnace, a flame heating, an electrical heating, a high-frequency heating, and an induction heating.

[0181] By the above methods, the hot stamped component according to the present embodiment is obtained. A tempering treatment at 130° C. to 600° C. may be performed after hot stamping for softening, or a baking hardening treatment after painting may be performed. In addition, a portion of the hot stamped component may be tempered by laser irradiation or the like to provide a partially softened region.EXAMPLES

[0182] Next, examples of the present invention will be described. Conditions in the examples are one example of conditions employed to confirm the feasibility and effects of the present invention, but the present invention is not limited to these examples. The present invention may employ various conditions to achieve the object of the present invention without departing from the scope of the present invention.

[0183] Slabs manufactured by casting molten steel having a chemical composition shown in Tables 1A to 1F were held in a temperature range of 1200° C. or higher for 20 minutes or longer, and then subjected to hot rolling, coiling, and cold rolling. The final rolling was performed under conditions shown in Tables 2A to 2E.

[0184] Note that after the completion of the finish rolling, the average cooling rate of cooling after a lapse of 5.0 seconds or more was 10° C. / s or faster, and the cooling stop temperature was 550° C. to 650° C. In addition, the total reduction of cold rolling was 50% or less.

[0185] The obtained steel sheets for hot stamping were subjected to hot stamping under the conditions shown in Tables 2A to 2E, and then cooled to the temperature range of 250° C. or lower at an average cooling rate of 20° C. / s or faster. As a result, the hot-stamping formed bodies shown in Tables 3A to 3G were obtained.

[0186] However, for some examples, as described in the tables, plating or heating treatment for softening were performed.

[0187] The underlines in the tables indicate that it is outside the scope of the present invention, falls outside the preferable manufacturing conditions, or the characteristic value is not preferable.

[0188] The microstructure of the hot stamped component according to the present invention consisted of, by area %, a total of 90% or more of martensite, bainite and tempered martensite, and 10% or less of ferrite and residual austenite. In addition, the sheet thickness of the hot stamped component according to the present invention was 0.5 to 3.5 mm.

[0189] Measurements of the microstructure of the hot stamped component and the measurement of the mechanical properties of the hot stamped component were performed by the above-described methods.

[0190] The bending test according to the VDA standard (VDA238-100: 2017-04) is widely performed on components for vehicle, but the bending test targets only flat sheet. Therefore, this VDA standard cannot evaluate the bendability of the hot stamped component with shapes other than flat sheet shape. On the other hand, when the hot stamped component has a bent portion, the bend portion is affected by such as the curvature of the bent portion. For this reason, the inventors considered that it is appropriate to evaluate the bendability according to this VDA standard using a hot stamped component with a flat sheet shape as a test material. Therefore, the bending test was performed on a hot stamped component with a flat sheet shape obtained by hot stamping without bending (using a die that can obtain a hot stamped component without a bent portion). In addition, since the rolling direction of the hot stamped component was known in advance, the rolling direction of the hot stamped component was determined without determining of the rolling direction by evaluation using the above-mentioned determination method. For the bending test machine, a SHIMADZU AUTOGRAPH 20 kN was used.

[0191] When the tensile strength TS was 2300 MPa or more, it was determined as having high strength and acceptable, and when the tensile strength TS was less than 2300 MPa, it was determined as not having high strength and unacceptable.

[0192] When the load at the ½ stroke of the stroke at the maximum load was 8050 N or more, it was determined as having excellent bendability and acceptable. On the other hand, when the load at the ½ stroke of the stroke at the maximum load was less than 8050 N, it was determined as not having excellent bendability and unacceptable. However, in a case where the sheet thickness of the hot stamped component was less than 1.6 mm, where t was the sheet thickness of the hot stamped component, when the load at the ½ stroke of the stroke at the maximum load was 8050×t / 1.6 (N) or more, it was determined as having excellent bendability and acceptable. On the other hand, when the load at the ½ stroke of the stroke at the maximum load was less than 8050×t / 1.6 (N), it was determined as not having excellent bendability and unacceptable. Note that in a case where the sheet thickness of the hot stamped component was less than 1.6 mm, the value obtained by multiplying the load at the ½ stroke by 1.6 / t (t is the sheet thickness in mm) was mentioned in the “Load at ½ stroke” in Tables 3 A to 3G.TABLE 1ASteelChemical composition (mass %) remainder being Fe and impuritiesNo.CSiMnPSNOAlNbTiCrMoBOthersNotes10.380.5500.570.0050.00050.00160.00160.04600.03600.0200.3500.2300.0021Comparative steel20.410.3300.300.0040.00210.00460.00270.05200.02600.0370.1400.1500.0034Steel of present invention30.430.5800.490.0050.00060.00400.00120.05900.04100.0470.4300.2100.0033Steel of present invention40.470.4400.450.0090.00130.00180.00120.04500.02300.0430.1900.2000.0018Steel of present invention50.550.3800.570.0110.00200.00280.00170.04200.03300.0300.4300.1900.0026Steel of present invention60.660.2700.560.0050.00200.00240.00150.04400.03300.0220.2300.2300.0026Steel of present invention70.720.5000.290.0090.00040.00220.00330.05200.03600.0200.1700.2400.0030Comparative steel80.460.0080.570.0060.00040.00460.00170.04000.01500.0300.3200.1700.0031Comparative steel90.460.0200.350.0090.00170.00420.00290.06100.02900.0390.2300.1800.0021Steel of present invention100.440.0700.350.0080.00130.00290.00250.04700.02700.0340.1100.1800.0023Steel of present invention110.440.1400.240.0080.00180.00210.00140.05600.04100.0250.1700.1800.0025Steel of present invention120.460.2600.470.0090.00150.00380.00100.05800.03100.0360.1600.1900.0022Steel of present invention130.450.4400.390.0040.00180.00230.00100.06100.03800.0390.3800.1800.0019Steel of present invention140.470.8700.320.0060.00200.00460.00160.05500.01900.0190.2000.2200.0025Steel of present invention150.471.6000.490.0040.00070.00370.00250.04100.03400.0350.3100.2100.0024Steel of present invention160.452.7000.360.0070.00180.00220.00300.04500.02000.0270.2300.1400.0032Steel of present invention170.473.2000.330.0050.00180.00400.00200.04500.01800.0400.3000.2100.0030Comparative steel180.450.2500.050.0070.00120.00330.00250.05500.03600.0470.3300.2300.0032Comparative steel190.440.6600.160.0040.00080.00370.00150.04400.01500.0380.3200.1800.0034Steel of present invention200.460.4800.240.0060.00200.00290.00330.05700.03900.0330.2200.1300.0029Steel of present invention210.450.6300.390.0070.00150.00210.00190.05000.03600.0480.3500.1500.0022Steel of present invention220.450.5100.460.0110.00090.00160.00230.04900.02200.0250.4100.2000.0028Steel of present invention230.440.4800.550.0070.00200.00390.00120.05000.02800.0310.3400.1900.0027Steel of present invention240.450.4500.840.0040.00070.00190.00240.03900.02100.0330.2400.1600.0034Comparative steel250.470.2200.350.0060.00130.00170.00330.04900.02100.0370.3800.1800.0016Steel of present invention260.470.5700.290.0120.00130.00370.00110.04000.02900.0290.3400.2300.0032Steel of present inventionThe underline indicates that it is outside the scope of the present invention.TABLE 1BSteelChemical composition (mass %) remainder being Fe and impuritiesNo.CSiMnPSNOAlNbTiCrMoBOthersNotes270.460.4500.240.0250.00210.00320.00190.05800.02400.0370.1100.2400.0022Steel of present invention280.450.2700.350.0460.00080.00200.00170.03900.03100.0410.1400.1200.0029Steel of present invention290.440.5900.390.0830.00190.00230.00310.04700.01300.0260.1500.2000.0027Steel of present invention300.450.2100.550.1200.00210.00300.00100.04300.02300.0290.3300.2200.0030Comparative steel310.440.5800.280.0100.00120.00240.00260.06100.02800.0200.1100.2400.0023Steel of present invention320.440.2500.490.0110.00280.00280.00230.04900.02100.0470.1900.1400.0030Steel of present invention330.470.4000.260.0080.00430.00410.00110.05900.02400.0480.2600.2300.0028Steel of present invention340.470.6400.470.0050.00750.00390.00220.05300.02000.0280.2600.1300.0029Steel of present invention350.460.3500.550.0040.00920.00410.00110.05800.01600.0350.1400.1900.0029Steel of present invention360.440.2800.390.0120.01340.00420.00160.05500.01400.0350.4300.1700.0032Comparative steel370.470.4100.380.0100.00030.00120.00140.04200.02300.0350.1400.1400.0030Steel of present invention380.470.5900.550.0100.00120.00220.00130.05300.02000.0220.1800.2000.0023Steel of present invention390.440.5300.550.0060.00110.00470.00130.04900.01900.0430.4100.1600.0033Steel of present invention400.460.5200.480.0080.00150.00650.00220.04900.03600.0250.2800.2200.0034Steel of present invention410.470.6600.250.0060.00200.00890.00190.04600.02800.0210.2800.1500.0034Steel of present invention420.440.3100.570.0090.00120.01210.00160.04000.01500.0260.2000.2300.0026Comparative steel430.460.4800.570.0060.00150.00340.00170.04400.01700.0370.1900.1500.0017Steel of present invention440.450.5300.490.0100.00130.00160.00380.05800.01300.0320.2500.1300.0025Steel of present invention450.450.2800.490.0060.00120.00190.00580.04100.02900.0380.2500.2000.0034Steel of present invention460.460.4200.530.0110.00040.00190.00840.05100.02400.0460.2700.2200.0028Steel of present invention470.440.2400.250.0080.00110.00430.01760.05900.02200.0280.4100.1800.0022Steel of present invention480.460.2900.550.0080.00120.00260.02400.05700.03400.0250.2600.2200.0031Comparative steel490.450.4700.280.0090.00090.00400.00240.00060.01500.0370.4300.2300.0022Comparative steel500.460.2100.370.0120.00110.00380.00090.00190.02000.0350.2900.1900.0022Steel of present invention510.470.5600.530.0060.00180.00260.00200.00520.03400.0410.1300.1600.0017Steel of present invention520.440.4200.260.0090.00150.00260.00260.01300.02700.0400.2900.1500.0018Steel of present inventionThe underline indicates that it is outside the scope of the present invention.TABLE 1CSteelChemical composition (mass %) remainder being Fe and impuritiesNo.CSiMnPSNOAlNbTiCrMoBOthersNotes530.450.5000.270.0070.00210.00190.00160.03900.01300.0410.2600.1700.0017Steel of present invention540.450.3200.320.0100.00050.00410.00180.08200.02700.0200.1200.1800.0032Steel of present invention550.470.6700.530.0100.00200.00230.00230.18000.04000.0190.3800.2100.0021Steel of present invention560.470.6000.300.0090.00210.00350.00330.25000.03200.0210.1100.1500.0029Steel of present invention570.450.5500.530.0110.00140.00320.00280.32000.04000.0290.2400.2000.0029Steel of present invention580.460.4700.550.0100.00190.00380.00090.48000.04100.0410.1100.1700.0023Steel of present invention590.450.5600.310.0060.00120.00250.00310.62000.01500.0420.3600.1700.0023Comparative steel600.460.5600.330.0090.00200.00420.00150.05200.00080.0310.2300.1900.0018Comparative steel610.440.6200.440.0100.00070.00320.00210.05000.00120.0340.3700.2200.0026Steel of present invention620.450.5700.380.0090.00060.00160.00320.06000.00390.0480.1700.1700.0026Steel of present invention630.450.4000.350.0120.00030.00230.00110.04900.00760.0200.1600.2400.0034Steel of present invention640.460.3000.550.0090.00140.00400.00280.05100.01200.0380.4300.1400.0022Steel of present invention650.450.2800.490.0070.00040.00400.00130.04500.01800.0340.1900.1700.0033Steel of present invention660.450.4000.270.0110.00110.00420.00130.04200.03400.0250.2000.2400.0020Steel of present invention670.450.2200.440.0120.00030.00270.00140.05100.05600.0390.1900.1200.0023Steel of present invention680.450.6200.440.0070.00090.00360.00300.05700.08800.0440.1600.1900.0030Steel of present invention690.470.4700.550.0070.00020.00180.00090.05800.13300.0290.1700.1400.0026Comparative steel700.460.6200.350.0110.00180.00280.00300.03900.02200.0070.2600.1200.0024Comparative steel710.460.5600.320.0050.00030.00150.00290.06100.01400.0130.3500.2400.0019Steel of present invention720.440.4400.420.0040.00200.00160.00090.04400.02800.0220.2200.1200.0019Steel of present invention730.460.3300.270.0050.00130.00390.00290.05300.03800.0380.1400.1200.0023Steel of present invention740.450.5400.340.0070.00180.00420.00250.05400.01600.0470.4200.2200.0018Steel of present invention750.450.5900.330.0050.00080.00240.00170.05000.02600.0620.2800.1500.0031Steel of present invention760.450.3300.280.0120.00140.00220.00190.05900.03100.0750.2900.2300.0032Steel of present invention770.470.5700.280.0120.00020.00160.00150.05000.02100.0870.1800.1500.0026Steel of present invention780.460.3100.390.0080.00120.00380.00200.04100.02300.1210.2300.2300.0018Comparative steel790.450.2900.520.0070.00190.00330.00270.05200.03200.0400.0070.1500.0018Comparative steelThe underline indicates that it is outside the scope of the present invention.TABLE 1DSteelChemical composition (mass %) remainder being Fe and impuritiesNo.CSiMnPSNOAlNbTiCrMoBOthersNotes 800.450.2500.520.0100.00090.00340.00130.06100.01400.0320.0180.2300.0022Steel of present invention 810.450.6700.350.0070.00070.00240.00140.05500.01300.0340.1100.1800.0024Steel of present invention 820.440.5500.500.0100.00090.00250.00160.04800.02100.0270.2800.1700.0025Steel of present invention 830.440.2500.330.0090.00210.00410.00210.05300.03700.0200.3500.1800.0033Steel of present invention 840.440.4500.330.0060.00190.00370.00210.05200.01900.0370.4800.2400.0028Steel of present invention 850.460.2800.430.0080.00100.00270.00220.04600.02100.0310.6500.1700.0017Steel of present invention 860.440.3300.250.0070.00050.00170.00160.04600.01700.0480.8800.1600.0018Steel of present invention 870.460.4100.320.0120.00080.00270.00180.05500.02000.0191.2200.1800.0018Comparative steel 880.460.5300.410.0110.00050.00460.00200.04600.01700.0190.1400.0200.0018Comparative steel 890.440.6000.290.0080.00060.00210.00150.04300.01600.0430.1900.0700.0019Steel of present invention 900.440.6300.330.0080.00210.00190.00240.05800.03600.0300.4100.1100.0023Steel of present invention 910.460.5600.500.0050.00130.00280.00260.04200.03200.0470.3100.1900.0027Steel of present invention 920.440.6600.490.0080.00140.00360.00260.04700.03100.0340.3200.3300.0021Steel of present invention 930.460.5800.240.0050.00160.00190.00160.06100.03100.0460.3300.5600.0022Steel of present invention 940.460.4800.530.0070.00020.00350.00260.05000.03500.0420.2200.7800.0029Steel of present invention 950.460.2500.390.0060.00030.00440.00120.04300.02400.0280.3900.9300.0024Steel of present invention 960.440.4200.270.0040.00050.00240.00150.05400.02500.0220.2301.2300.0024Comparative steel 970.440.4600.380.0070.00030.00450.00120.05400.03000.0290.2600.2300.0004Comparative steel 980.450.3000.340.0110.00170.00290.00310.05100.02700.0210.1100.1400.0007Steel of present invention 990.440.2500.370.0090.00190.00330.00320.04600.01900.0330.1700.2200.0012Steel of present invention1000.450.6100.570.0100.00110.00400.00120.04100.04000.0320.1300.1700.0019Steel of present invention1010.450.5800.400.0070.00080.00240.00160.06100.01300.0330.2900.1900.0032Steel of present invention1020.460.2200.420.0050.00050.00310.00230.04500.03000.0390.4100.2100.0055Steel of present invention1030.440.6200.460.0050.00040.00360.00290.06000.02600.0350.3800.2100.0072Steel of present invention1040.460.3500.540.0120.00060.00200.00330.04300.02600.0320.1200.2100.0086Steel of present invention1050.460.2300.370.0050.00150.00310.00330.05300.02500.0260.1800.2100.0115Comparative steelThe underline indicates that it is outside the scope of the present invention.TABLE 1ESteelChemical composition (mass %) remainder being Fe and impuritiesNo.CSiMnPSNOAlNbTiCrMoBOthersNotes1060.450.5300.300.0070.00030.00240.00110.05200.04100.0470.2100.2100.0024Co = 0.06Steel of present invention1070.470.2700.420.0060.00210.00320.00300.04200.02400.0240.1900.2000.0016Co = 1.30Steel of present invention1080.470.3900.400.0120.00040.00200.00090.04100.03300.0320.2800.1300.0021Co = 2.50Steel of present invention1090.450.6600.330.0060.00050.00400.00290.05300.02600.0330.3900.1500.0029Ni = 0.03Steel of present invention1100.470.3900.440.0090.00190.00250.00150.05200.02700.0320.2600.1200.0032Ni = 1.10Steel of present invention1110.460.2200.480.0110.00180.00210.00100.03900.03700.0360.3800.1200.0020Ni = 2.60Steel of present invention1120.470.3300.520.0070.00080.00220.00120.04700.02500.0310.2200.1400.0034Cu = 0.07Steel of present invention1130.460.4400.570.0090.00180.00460.00170.04000.01600.0310.3700.1900.0019Cu = 1.20Steel of present invention1140.460.6600.430.0050.00020.00200.00320.03900.02900.0380.2900.2300.0017Cu = 2.70Steel of present invention1150.460.2600.560.0040.00060.00370.00150.05700.02700.0280.3900.1900.0017V = 0.06Steel of present invention1160.440.2300.260.0120.00060.00310.00140.05800.01500.0330.1200.1600.0019V = 0.90Steel of present invention1170.440.6100.390.0070.00210.00280.00300.06100.02300.0290.4200.1500.0031V = 2.20Steel of present invention1180.460.2200.280.0060.00030.00300.00290.04600.04000.0210.1400.1300.0025W = 0.09Steel of present invention1190.450.6200.440.0050.00100.00350.00100.05000.01400.0190.4100.2100.0033W = 1.50Steel of present invention1200.470.6200.380.0110.00100.00240.00300.05700.03100.0200.3200.1500.0029W = 2.60Steel of present invention1210.440.6200.450.0120.00190.00280.00260.04100.02300.0340.1200.2200.0032  Ca = 0.0016Steel of present invention1220.460.2500.470.0070.00130.00260.00140.04100.03500.0230.1600.1600.0017  Ca = 0.0120Steel of present invention1230.440.6200.320.0120.00020.00360.00320.04600.02100.0290.4000.1700.0020  Ca = 0.0860Steel of present invention1240.450.4700.410.0070.00180.00270.00250.04100.04000.0370.3400.1500.0034 Mg = 0.0018Steel of present invention1250.460.6400.530.0080.00180.00230.00210.05200.02300.0250.4300.2300.0034 Mg = 0.2100Steel of present invention1260.450.6400.390.0060.00050.00270.00170.03900.02600.0410.1900.2400.0026 Mg = 0.9200Steel of present invention1270.460.6600.370.0120.00210.00170.00160.05900.01800.0330.3900.1500.0023REM = 0.0016Steel of present invention1280.440.3700.360.0110.00040.00380.00220.05000.03000.0340.1100.1200.0022REM = 0.1300Steel of present invention1290.450.6500.510.0120.00130.00270.00330.04400.01600.0240.3300.2200.0019REM = 0.6700Steel of present inventionTABLE 1FSteelChemical composition (mass %) remainder being Fe and impuritiesNo.CSiMnPSNOAlNbTiCrMoBOthersNotes1300.450.6200.380.0070.00060.00260.00190.04200.02200.0370.1600.1600.0020Sb = 0.006Steel of present invention1310.450.6300.390.0050.00170.00370.00100.04400.03400.0270.1400.1400.0020Sb = 0.140Steel of present invention1320.450.4700.470.0090.00090.00310.00110.04000.01500.0420.1900.1700.0030Sb = 0.850Steel of present invention1330.460.2200.470.0050.00130.00260.00130.05400.04000.0310.2000.2300.0034Sn = 0.003Steel of present invention1340.470.6600.310.0050.00100.00300.00150.05500.02100.0360.1600.1400.0033Sn = 0.120Steel of present invention1350.440.6700.330.0060.00190.00400.00170.05000.02800.0360.3500.2400.0033Sn = 0.790Steel of present invention1360.440.4100.500.0090.00040.00380.00170.04000.02100.0200.1200.2400.0031Zr = 0.005Steel of present invention1370.450.5500.320.0070.00120.00280.00130.04800.04000.0400.2100.1500.0017Zr = 0.090Steel of present invention1380.460.3600.260.0050.00210.00200.00150.05200.02700.0350.1400.1200.0018Zr = 0.720Steel of present invention1390.470.5100.390.0100.00140.00150.00250.05800.03200.0220.1700.1700.0032As = 0.003Steel of present invention1400.460.2600.530.0080.00160.00250.00120.05200.02200.0280.3400.1800.0025As = 0.042Steel of present invention1410.460.5800.500.0070.00200.00370.00330.05500.01400.0450.3400.1600.0019As = 0.093Steel of present invention1420.450.4200.480.0120.00030.00330.00220.04700.03700.0360.4100.1500.0020Co = 1.40, Steel of Ni = 1.20present invention1430.440.4300.270.0100.00100.00360.00270.05900.03700.0220.4100.2200.0022Co = 1.30, Steel of Cu = 1.40present invention1440.450.5500.270.0100.00100.00460.00300.04100.02000.0330.2000.1700.0025Co = 1.40, Steel of W = 1.60present invention1450.450.2700.430.0070.00130.00250.00240.05800.04000.0340.2300.2000.0018Co = 1.50, Steel of Mg = 0.1900present invention1460.440.4900.420.0100.00190.00230.00330.03900.01600.0440.1800.2000.0033Ni = 1.30, Steel of Cu = 1.20present invention1470.460.5400.340.0060.00040.00290.00170.05800.02500.0480.2000.1500.0034Ni = 1.20, Steel of W = 1.40present invention1480.460.3000.480.0050.00070.00160.00270.06100.02500.0340.3100.2200.0027Ni = 1.10, Steel of Mg = 0.1800present invention1490.470.2800.310.0080.00130.00280.00160.04500.02100.0460.2600.1800.0017Cu = 1.10, Steel of W = 1.30present invention1500.440.2100.560.0110.00170.00400.00330.05400.04000.0410.2900.1900.0018Cu = 1.20, Steel of Mg = 0.2200present invention1510.440.2600.540.0050.00040.00250.00260.05800.01700.0420.2600.1900.0026W = 1.40, Steel of Mg = 0.2100present inventionTABLE 2AFinal rollingRolling CoolingHot stampingreductionRollingTime HeatingManu-at one standreduction atuntiltem-facturingSteelbefore final final standstartingperatureHoldingNo.No.stand %%coolings° C.timesNotes 1 154516.9920478Comparative example 2 253516.4882481Present invention example 3 351516.6919495Present invention example 4 453556.2892465Present invention example 5 555566.3881466Present invention example 6 652545.2914495Present invention example 7 753516.3906479Comparative example 8 850547.1911481Comparative example 9 954555.9885477Present invention example101050525.4882481Present invention example111153525.7896478Present invention example121252557.4894478Present invention example131353535.3892495Present invention example141454565.9904465Present invention example151552556.5896478Present invention example161654547.2916477Present invention example171752505.4905492Comparative example181852516.7903489Comparative example191954526.7912493Present invention example202055507.4882474Present invention example212151516.6896474Present invention example222250566.5882480Present invention example232352517.0889485Present invention example242451535.0911487Comparative example252551546.3894479Present invention example262654506.6915472Present invention example272755506.0898479Present invention example282850536.2881473Present invention example292953557.4899470Present invention example303051525.4885468Comparative example313150556.8918484Present invention example323252556.5897475Present invention example333352506.0894473Present invention example343452565.1903491Present invention example353553505.6918465Present invention example363655525.6888482Comparative example373754506.7909466Present invention exampleThe underline indicates that the manufacturing condition is not preferable.TABLE 2BFinal rollingCoolingRolling reductionRollingTime Hot stampingManu-at one standreduction untilHeatingfacturingSteelbefore final at final startingtemperatureHoldingNo.No.stand %stand %coolings° C.timesNotes383855526.6904472Present invention example393954517.1916477Present invention example404052527.3918486Present invention example414151546.8887471Present invention example424251507.2906484Comparative example434354525.3893476Present invention example444451555.7903491Present invention example454551525.6914489Present invention example464652536.5900469Present invention example474753526.0917470Present invention example484855506.6906482Comparative example494952525.3919490Comparative example505055566.9887495Present invention example515152547.1897467Present invention example525254536.1882471Present invention example535355546.2910467Present invention example545453506.8900488Present invention example555555516.2881468Present invention example565653517.2902495Present invention example575752545.7911483Present invention example585852556.4918494Present invention example595950525.7882473Comparative example606052525.1882482Comparative example616153555.3900491Present invention example626253525.1908478Present invention example636353536.2895492Present invention example646453506.1912480Present invention example656554545.2912479Present invention example666652515.4891484Present invention example676751565.5909478Present invention example686852527.3909484Present invention example696955526.6889483Comparative example707050565.3897493Comparative example717155525.9897477Present invention example727250555.3910478Present invention example737351546.8891493Present invention example747453546.4898485Present invention example757552505.9915485Present invention exampleThe underline indicates that the manufacturing condition is not preferable.TABLE 2CFinal rollingCoolingRolling reductionRollingTime Hot stampingManu-at one standreduction atuntilHeatingfacturingSteelbefore final final standstartingtemperatureHoldingNo.No.stand %%coolings° C.timesNotes 76 7654527.4897493Present invention example 77 7751505.5905465Present invention example 78 7853566.3886494Comparative example 79 7955506.2881482Comparative example 80 8054556.4894491Present invention example 81 8150525.8894488Present invention example 82 8255545.1897467Present invention example 83 8352536.4903483Present invention example 84 8454507.0911483Present invention example 85 8554557.4907487Present invention example 86 8655515.2888476Present invention example. 87 8754546.4898488Comparative example 88 8854505.8910478Comparative example 89 8950507.0884478Present invention example 90 9054536.7902474Present invention example 91 9155525.0900476Present invention example 92 9254515.2907495Present invention example 93 9353546.0881480Present invention example 94 9455506.6901471Present invention example 95 9554555.1911478Present invention example 96 9652525.0905494Comparative example 97 9754527.0894484Comparative example 98 9854525.5905495Present invention example 99 9951565.6917487Present invention example10010055555.9914485Present invention example10110152505.0899470Present invention example10210251516.8915483Present invention example10310355567.1887477Present invention example10410450515.3919466Present invention example10510554505.0882466Comparative example10610652535.5905484Present invention example10710751506.2902477Present invention example10810850545.2894472Present invention example10910953517.2916482Present invention example11011053507.1915492Present invention example11111151526.1903479Present invention exampleThe underline indicates that the manufacturing condition is not preferable.TABLE 2DFinal rollingCoolingHot stampingRolling reductionRollingTime HeatingManu-at one standreduction untiltemper-facturingSteelbefore final at final startingatureHoldingNo.No.stand %stand %coolings° C.timesNotes11211250556.9880489Present invention example11311353565.3886472Present invention example11411452555.9915492Present invention example11511552566.6899466Present invention example11611654557.4898495Present invention example11711755517.3904466Present invention example11811855525.3884484Present invention example11911951507.0918493Present invention example12012053506.6903492Present invention example12112153525.1887488Present invention example12212253527.2881470Present invention example12312352535.0882494Present invention example12412453555.8886478Present invention example12512550556.2914488Present invention example12612653517.0896473Present invention example12712754536.9892477Present invention example12812850506.2880481Present invention example12912950546.0900480Present invention example13013051526.4898481Present invention example13113155537.2901465Present invention example13213253507.3903491Present invention example13313351556.2910494Present invention example13413453526.8889472Present invention example13513553537.0900472Present invention example13613654517.3900480Present invention example13713755556.2920485Present invention example13813850545.4918480Present invention example13913955566.5890494Present invention example.14014052565.3907476Present invention example14114154527.2915494Present invention example14214255565.5887489Present invention example14314355526.3885465Present invention example14414453526.3882488Present invention example14514553535.5916470Present invention example14614654555.8885486Present invention example14714755506.5918480Present invention example14814855506.1910485Present invention example14914954525.2904486Present invention example15015053505.4895482Present invention exampleTABLE 2EFinal rollingCoolingHot stampingRolling reductionRollingTime HeatingManu-at one standreduction untiltemper-facturingSteelbefore final at final startingatureHoldingNo.No.stand %stand %coolings° C.timeNotes15115152527.0889482Present invention example152 1120106.4880494Comparative example153 1120207.4920481Comparative example154 1430305.2910465Comparative example155 2240306.1881466Comparative example156 1430406.3899478Comparative example157 2040405.1919470Comparative example158 2020505.8890477Comparative example159 1450205.8909471Comparative example160 1255500.4913478Comparative example161 2252542.2919475Comparative example162 1451514.1904485Comparative example163 2154546.1895470Present invention example164 1251566.7911471Present invention example165 1351545.5892487Present invention example166 1150535.3886466Present invention example167 2250567.0909475Present invention example168 2155535.1903468Present invention example169 1155507.1897470Present invention example170 1451525.5881489Present invention example171 2252546.3745478Comparative example172 2250526.3843490Present invention example173 1453545.2895482Present invention example174 2053525.6952483Present invention example175 2253535.01023 489Comparative example176 1451516.0890 38Comparative example177 2251517.0899 62Present invention example178 1451516.7885481Present invention example179 1451526.7908955Present invention example180 1352535.28911258 Comparative example181 1153506.6907466Present invention example182 1250526.8881476Present invention example183 2154536.5880478Present invention example184 1451567.4895486Present invention example185 1250536.4883489Present invention example186 2054525.2911482Present invention example187 1350506.2883492Present invention example188 1353505.3899488Present invention exampleThe underline indicates that the manufacturing condition is not preferable.TABLE 3AHot stamped componentManu-PartiallyMaximum value of poleAverage value TensileLoad at facturingSteelsofteneddensitis of texture of priorof block strength½ strokeNo.No.PlatingTemperingregionaustenite -sizes μmMPaNNotes 1 16.60.6920838149Comparative example 2 24.40.8123068131Present invention example 3 39.00.7424458090Present invention example 4 44.70.7025218073Present invention example 5 54.00.7627628129Present invention example 6 64.40.6828558151Present invention example 7 79.00.7429377826Comparative example 8 88.80.7022148146Comparative example 9 98.60.8023258127Present invention example10104.00.8524368152Present invention example11119.70.7524638120Present invention example12125.60.8523878137Present invention example131310.1 0.7723618153Present invention example14143.40.7123858089Present invention example15154.90.8424688091Present invention example16168.30.7023178119Present invention example17179.80.7822168076Comparative example18186.00.8221878072Comparative example19193.90.7423418128Present invention example20204.40.8124608148Present invention example21219.40.7924188080Present invention example22228.20.7823728081Present invention example23234.60.7325208093Present invention example24242.10.8523778004Comparative example25254.00.7924008093Present invention example26269.60.8523928148Present invention example27279.30.7224518093Present invention exampleThe underline indicates that it is outside the scope of the present invention, or the characteristic value is not preferable.TABLE 3BHot stamped componentManu-PartiallyMaximum value of poleAverage value TensileLoad at facturingSteelsofteneddensitis of texture of priorof block strength½ strokeNo.No.PlatingTemperingregionaustenite -sizes μmMPaNNotes28287.40.8124698130Present invention example29294.60.7124788053Present invention example30302.70.6924207832Comparative example31314.10.8524968141Present invention example32329.80.7323678102Present invention example33337.10.8424938139Present invention example343410.3 0.7925278077Present invention example35356.10.7523778067Present invention example36362.80.8324167838Comparative example37376.70.8123858099Present invention example38386.90.7023748116Present invention example39393.50.8323848134Present invention example40403.80.7223538150Present invention example41414.20.6825258077Present invention example42421.70.7224187972Comparative example43435.20.7325498125Present invention example44449.00.6925008076Present invention example45459.10.7325468146Present invention example46469.20.8223898096Present invention example47474.10.7224608056Present invention example48482.20.7723697885Comparative example49492.40.8525267913Comparative example50506.90.7924308065Present invention example51518.80.8425478125Present invention example52528.00.7923798096Present invention example53539.10.7823948143Present invention example54549.70.6924768075Present invention exampleThe underline indicates that it is outside the scope of the present invention, or the characteristic value is not preferable.TABLE 3CHot stamped componentManu-PartiallyMaximum value of poleAverage value TensileLoad at facturingSteelsofteneddensities of texture of priorof block strength½ strokeNo.No.PlatingTemperingregionaustenite -sizes μmMPaNNotes55556.00.7724738134Present invention example56566.10.8124178086Present invention example57576.80.7624378144Present invention example58586.80.8524478058Present invention example59592.60.7625477838Comparative example60608.00.6821758124Comparative example61619.20.7223118085Present invention example62629.80.7923638128Present invention example63635.50.7923558103Present invention example64646.20.6823758081Present invention example65654.70.8024848120Present invention example66665.80.8123528148Present invention example67676.10.7524548091Present invention example68683.90.8325478066Present invention example69691.90.7623757962Comparative example70703.70.7722268120Comparative example71717.40.7923748117Present invention example72724.10.8325348097Present invention example73733.50.6823668092Present invention example74747.30.7624408121Present invention example75756.00.7423558089Present invention example76766.60.7225338146Present invention example77777.20.7524868070Present invention example78782.30.7124657953Comparative example79798.30.8022988149Comparative example80807.90.7823368130Present invention example81817.00.8223758129Present invention exampleThe underline indicates that it is outside the scope of the present invention, or the characteristic value is not preferable.TABLE 3DHot stamped componentManu-PartiallyMaximum value of poleAverage value ofTensileLoad at facturingSteelsofteneddensities of texture of priorblock sizesstrength½ strokeNo.No.PlatingTemperingregionaustenite -sizes μmMPaNNotes 82 825.90.8023888095Present invention example 83 838.00.7324818126Present invention example 84 844.50.8125098077Present invention example 85 8510.3 0.7724448116Present invention example 86 863.80.7324418128Present invention example 87 872.60.8024577963Comparative example 88 886.40.7922448117Comparative example 89 896.70.8123288119Present invention example 90 903.50.8124518154Present invention example 91 918.40.8223908104Present invention example 92 923.50.7724428117Present invention example 93 934.00.8424898112Present invention example 94 947.10.8024148136Present invention example 95 954.20.8224268091Present invention example 96 962.20.6824037889Comparative example 97 973.90.8122098108Comparative example 98 983.30.7123488089Present invention example 99 997.80.8025288148Present invention example1001003.70.7125428102Present invention example1011017.00.8024008143Present invention example1021026.90.7724388120Present invention example1031036.70.7823948114Present invention example1041045.50.8024148055Present invention example1051052.10.7724267859Comparative example10610610.3 0.8224518074Present invention example1071077.40.7824798138Present invention example1081087.80.8524708106Present invention exampleThe underline indicates that it is outside the scope of the present invention, or the characteristic value is not preferable.TABLE 3EHot stamped componentManu-PartiallyMaximum value of poleAverage value TensileLoad at facturingSteelsofteneddensities of texture of priorof block strength½ strokeNo.No.PlatingTemperingregionaustenite -sizes μmMPaNNotes1091098.30.7024928115Present invention example1101106.80.7224248140Present invention example1111118.20.6923548078Present invention example1121126.90.7825308074Present invention example1131138.10.7824008152Present invention example11411410.2 0.8324198131Present invention example1151153.30.8025298093Present invention example1161167.80.7724148103Present invention example1171179.20.7224848121Present invention example1181189.30.8225418084Present invention example1191196.70.8423908090Present invention example1201207.70.6924158138Present invention example1211213.20.7025028154Present invention example12212210.1 0.6925128147Present invention example1231236.70.7324658112Present invention example1241247.70.7123628112Present invention example1251259.20.7224348126Present invention example1261266.50.8325248119Present invention example1271277.50.6825088136Present invention example1281285.80.8124098137Present invention example1291295.30.7924788093Present invention example1301303.40.8024648128Present invention example1311319.70.7523838118Present invention example1321329.50.8525458117Present invention example1331335.50,8324648081Present invention example1341343.40.7723968107Present invention example1351353.60.8524298141Present invention exampleTABLE 3FHot stamped componentManu-PartiallyMaximum value of poleAverage valueTensileLoad at facturingSteelsofteneddensities of texture of priorof block strength1 / 2 strokeNo.No.PlatingTemperingregionaustenite -sizes μmMPaNNotes1361368.10.8024588081Present invention example13713710.3 0.7824608146Present invention example1381387.80.7925278126Present invention example1391397.60.7324948134Present invention example1401408.70.8525018074Present invention example1411414.60.7725318092Present invention example1421427.70.7323728106Present invention example1431434.40.8323968078Present invention example1441449.10.8524648128Present invention example1451459.90.6825108122Present invention example1461469.40.7923768073Present invention example1471473.70.6825278107Present invention example1481486.50.8524578111Present invention example1491494.30.7923968137Present invention example1501509.20.7923988132Present invention example1511519.90.7325098134Present invention example152 111.90.7524257964Comparative example153 111.80.7225497965Comparative example154 142.20.7924417982Comparative example155 222.40.8425028002Comparative example156 142.70.8024918011Comparative example157 202.80.7224668039Comparative example158 202.20.8424247995Comparative example159 142.50.8125018011Comparative example160 122.30.7823727896Comparative example161 222.10.7123597923Comparative example162 142.40.7124517984Comparative exampleThe underline indicates that it is outside the scope of the present invention, or the characteristic value is not preferable.TABLE 3GHot stamped componentMaximum value ofAverage Load Manu-Partiallypole densities ofvalue of Tensileat ½facturingSteelsoftened texture of priorblock sizesstrengthstrokeNo.No.PlatingTemperingregionaustenite -μmMPaNNotes16321aluminum plating9.40.7825478104Present invention example16412aluminum-galvanized9.50.7325128117Present invention example16513aluminum-silicon5.10.7125408132Present invention exampleplating16611hot-dip galvanized6.10.7423998116Present invention example16722electrogalvanized6.70.7324878147Present invention example16821galvannealed6.60.8024908098Present invention example16911zinc-nickel plating7.50.7523878073Present invention example17014aluminum-5.80.7225408090Present invention examplemagnesium-zinc-based plating171222.50.9122657898Comparative example172227.90.8823348056Present invention example173149.20.7824188075Present invention example174208.30.9323868062Present invention example175221.91.3121567762Comparative example176142.40.8722597930Comparative example177228.20.7523468067Present invention example178149.60.7924818111Present invention example179147.60.8523358056Present invention example180132.21.2722037991Comparative example18111Tempering 8.90.7624568097Present invention exampletemperature 153° C.18212Tempering 9.30.8423638140Present invention exampletemperature 172° C.18321Tempering 9.50.7125318104Present invention exampletemperature 205° C.18414Tempering 6.50.7924348092Present invention exampletemperature 339° C.18512Tempering 7.20.7323548121Present invention exampletemperature 432° C.18620Tempering 10.2 0.7123698151Present invention exampletemperature 515° C.18713Tempering 5.80.8124598137Present invention exampletemperature 588° C.18813Partially4.10.7824488126Present invention examplesoftenedtreatmentThe underline indicates that it is outside the scope of the present invention, or the characteristic value is not preferable.From Tables 3A to 3G, it can be seen that the hot-stamping formed bodies according to the present invention examples had high strength and excellent bendability.On the other hand, it can be seen that in the hot-stamping formed bodies according to comparative examples, one or more of the properties deteriorated.INDUSTRIAL APPLICABILITYAccording to the above-described aspects of the present invention, it is possible to provide a hot stamped component having high strength and excellent bendability.

Claims

1. A hot stamped component comprising, as a chemical composition, by mass %:C: 0.40% to 0.70%;Si: 0.010% to 3.000%;Mn: 0.10% or more and less than 0.60%;P: 0.100% or less;S: 0.0100% or less;N: 0.0100% or less;O: 0.0200% or less;Al: 0.0010% to 0.5000%;Nb: 0.0010% to 0.1000%;Ti: 0.010% to 0.100%;Cr: 0.010% to 1.000%;Mo: 0.050% to 1.000%;B: 0.0005% to 0.0100%;Co: 0% to 3.00%;Ni: 0% to 3.00%;Cu: 0% to 3.00%;V: 0% to 3.00%;W: 0% to 3.00%;Ca: 0% to 0.1000%;Mg: 0% to 1.0000%;REM: 0% to 1.0000%;Sb: 0% to 1.000%;Sn: 0% to 1.000%;Zr: 0% to 1.000%;As: 0% to 0.100%; anda remainder: Fe and impurities,in a position at ¼ of a sheet thickness from a surface,in a texture of prior austenite, a maximum value of pole densities of an orientation group expressed by Euler angles of Φ=60° to 90°, φ1=60° to 90°, and φ2=450 is 3.0 or more,an average value of block sizes of martensite, tempered martensite and bainite is 1.20 m or less.

2. The hot stamped component according to claim 1 comprising, as the chemical composition, by mass %, one or more of:Co: 0.01% to 3.00%;Ni: 0.01% to 3.00%;Cu: 0.01% to 3.00%;V: 0.01% to 3.00%;W: 0.01% to 3.00%;Ca: 0.0001% to 0.1000%;Mg: 0.0001% to 1.0000%;REM: 0.0001% to 1.0000%;Sb: 0.001% to 1.000%;Sn: 0.001% to 1.000%;Zr: 0.001% to 1.000%; andAs: 0.001% to 0.100%.