Hot-stamp molded body and automotive component

Abstract

Provided is a hot-stamp molded body comprising a first region (11) that includes a steel sheet (11a) and that is the portion with the greatest thickness, and a second region (12) that includes a steel sheet (12a) and that is connected to the first region (11) directly or via a weld metal (13). The steel sheet (11a) and the steel sheet (12a) each have a reference hardness of not less than 400 HV1, and the absolute value of the difference therebetween is not more than 200 HV1. The quenching degree of the steel sheet (11a) is 0.90-1.10. The quenching degree of the steel sheet (12a) at a 10 mm position is 0.90-1.10. The quenching degree of the steel sheet (12a) at a 60 mm position is 0.40-0.80.

Description

Hot-stamped molded parts and automotive parts 【0001】 This invention relates to hot-stamped molded articles and automotive parts. 【0002】 To achieve both weight reduction and collision safety in automobiles, there is a demand for higher strength materials used in vehicles. For this reason, in recent years, hot-stamped steel up to 2.0 GPa has been put into practical use in vehicle bodies. Furthermore, so-called tailored property parts, which have different mechanical properties and / or thicknesses depending on the specific part within a single component, are frequently used. 【0003】 For example, Patent Document 1 discloses a method for manufacturing a tailored blank press-formed product, comprising: a welding step of welding a first metal sheet and a second metal sheet having different thicknesses to obtain a connected substrate in which both metal sheets are integrated; a heating step of heating the connected substrate to a temperature range in which the first metal sheet or the second metal sheet can be hardened; and a pressing step of applying a press to the connected substrate, which is in a hardenable temperature state, using a relatively low-temperature press die, in such a manner that when both sides of the metal sheet with the greater thickness of the first and second metal sheets are in contact with the forming surface of the press die, a predetermined clearance is secured between at least one surface of the metal sheet with the less thickness and the forming surface of the press die facing that surface, thereby simultaneously imparting a desired shape and hardening. 【0004】 Japanese Patent Publication No. 2004-58082 【0005】 The technology disclosed in Patent Document 1 involves welding two metal sheets of different thicknesses together and then performing hot stamping to impart a relatively stronger hardening effect to the metal sheet with the greater thickness. As a result, the strength of the metal sheet with the greater thickness can be increased. 【0006】 However, the inventors' investigations revealed that if a change in strength occurs simultaneously with a change in plate thickness, deformation concentration may occur in that area, potentially leading to fracture. 【0007】The present invention aims to solve the above problems and provide a hot-stamped molded body and an automotive part including the same that can suppress deformation concentration in areas where the plate thickness changes abruptly, when there are two or more parts with different plate thicknesses within a single part. 【0008】 This invention was made to solve the above problems and is characterized by the following hot-stamped molded articles and automotive parts. 【0009】 (1) A hot-stamped molded body comprising one or more steel plates, having a first region which is the thickest part of the hot-stamped molded body, and a second region comprising one or more steel plates which is directly connected to the first region or connected by weld metal, wherein a test piece taken from a predetermined position is subjected to a heat treatment in which it is heated to 900°C at a heating rate of 5°C / s and held for 2 min, immediately cooled to Ms+10°C at a cooling rate of 50°C / s, and then cooled to 25°C at a cooling rate of 20°C / s, and the Vickers hardness measured at the predetermined position is taken as the reference hardness at the predetermined position, and the value obtained by dividing the Vickers hardness measured at the predetermined position by the reference hardness is taken as the degree of hardness at the predetermined position, wherein the reference hardness of the steel plate constituting the first region and the steel plate constituting the second region are both 400 HV1 or more, and the absolute value of the difference between them is 200 HV1 or less, A hot-stamped molded body wherein the degree of hardening at the 1 / 4 thickness position of the steel plate constituting the first region is 0.90 to 1.10, the degree of hardening at the 1 / 4 thickness position of the steel plate constituting the second region at a point 10 mm away from the boundary with the steel plate constituting the first region or the weld metal, whichever is closer, is 0.90 to 1.10, and the degree of hardening at the 1 / 4 thickness position of the steel plate constituting the second region at a point 60 mm away from the boundary with the steel plate constituting the first region or the weld metal, whichever is closer, is 0.40 to 0.80. 【0010】(2) The hot-stamped molded article according to (1) above, wherein the product of the Vickers hardness and the maximum bending angle at a point 60 mm away from the boundary of the steel plate constituting the second region with the first region or the weld metal, whichever is closer, is 33,000 HV 1.5 degrees or more. 【0011】 (3) The chemical composition of the steel plate constituting the first region and the steel plate constituting the second region is, in mass%, C: 0.10 to 0.60%, Si: 0.01 to 2.00%, Mn: 0.10 to 3.00%, P: 0.050% or less, S: 0.0200% or less, N: 0.0200% or less, O: 0.100% or less, Al: 0.001 to 0.100%, Cr: 0.01 to 1.00%, Nb: 0 to 0.200%, Ti: 0 to 0.200%, Mo: 0 to 1.00%, B: 0 to 0.0100%, Co: 0 to 4.00%, Ni: 0 to 2.00%, Cu: 0 to 1.00%, V: 0 to 1.00%, A hot-stamped molded article as described in (1) above, comprising W: 0-1.00%, Ca: 0-0.100%, Mg: 0-0.100%, REM: 0-0.100%, Sb: 0-0.100%, Zr: 0-0.100%, Sn: 0-1.00%, As: 0-0.100%, the remainder being Fe and impurities. 【0012】(4) The chemical composition of the steel plate constituting the first region and the steel plate constituting the second region is, in mass%, C: 0.10 to 0.60%, Si: 0.01 to 2.00%, Mn: 0.10 to 3.00%, P: 0.050% or less, S: 0.0200% or less, N: 0.0200% or less, O: 0.100% or less, Al: 0.001 to 0.100%, Cr: 0.01 to 1.00%, Nb: 0 to 0.200%, Ti: 0 to 0.200%, Mo: 0 to 1.00%, B: 0 to 0.0100%, Co: 0 to 4.00%, Ni: 0 to 2.00%, Cu: 0 to 1.00%, V: 0 to 1.00%, A hot-stamped molded article as described in (2) above, comprising W: 0-1.00%, Ca: 0-0.100%, Mg: 0-0.100%, REM: 0-0.100%, Sb: 0-0.100%, Zr: 0-0.100%, Sn: 0-1.00%, As: 0-0.100%, the remainder being Fe and impurities. 【0013】 (5) Automotive parts comprising a hot-stamped molded body as described in any of (1) to (4) above. 【0014】 According to the present invention, when there are two or more parts with different plate thicknesses within a single component, it is possible to obtain a hot-stamped molded body and an automotive part containing the same that can suppress deformation concentration in parts where the plate thickness changes abruptly. 【0015】Figure 1A is a schematic perspective view of a hot-stamped molded body according to one embodiment of the present invention. Figure 1B is a top view of a hot-stamped molded body according to one embodiment of the present invention. Figure 1C is an end view of the a-a portion of Figure 1B. Figure 2 is a schematic diagram showing a cylindrical test specimen made using a test piece. Figure 3A is a schematic perspective view of a hot-stamped molded body according to another embodiment of the present invention. Figure 3B is a top view of a hot-stamped molded body according to another embodiment of the present invention. Figure 3C is an end view of the b-b portion of Figure 3B. Figure 3D is an end view of the c-c portion of Figure 3B. Figure 4A is a schematic perspective view of a hot-stamped molded body according to another embodiment of the present invention. Figure 4B is a top view of a hot-stamped molded body according to another embodiment of the present invention. Figure 4C is an end view of the d-d portion of Figure 4B. Figure 4D is an end view of the e-e portion of Figure 4B. Figure 5A is a plan view of a test piece S before testing, used for bending tests. Figure 5B is a schematic diagram for explaining bending tests. Figure 6A is a schematic diagram illustrating a method for manufacturing a hot-stamped molded article according to one embodiment of the present invention, showing the state immediately after press molding. Figure 6B is a schematic diagram illustrating a method for manufacturing a hot-stamped molded article according to one embodiment of the present invention, showing the process of dividing the mold. 【0016】 The inventors of this invention investigated a method to suppress deformation concentration in areas where the plate thickness changes abruptly, when there are two or more parts with different plate thicknesses within a single component, and as a result, obtained the following findings. 【0017】 Within a single component, if the thickness is increased and high strength is provided in areas where strength is required, and the thickness is reduced and strength is kept low in areas where flexibility is required, it can be suitably used, for example, as an automotive component where both weight reduction and collision safety are required. 【0018】 However, when joining two steel plates of different thicknesses and performing hot stamping, if the thicker plate is subjected to relatively stronger heat treatment, the areas where the plate thickness changes and the areas where the strength changes will overlap. 【0019】Therefore, by applying the same level of strong heat treatment to the area of ​​the thinner steel plate, from the boundary with the thicker steel plate to a point a reasonable distance away, a distance difference can be created between the point of abrupt change in thickness and the point of abrupt change in strength, thereby mitigating deformation concentration. 【0020】 This invention is based on the above findings. The requirements of this invention will be described in detail below. 【0021】 1. Hot Stamped Molding Figure 1A is a schematic perspective view of a hot stamped molding according to one embodiment of the present invention. In the figure, the hatched areas indicate the weld metal. Figure 1B is a top view of the hot stamped molding according to one embodiment of the present invention, and Figure 1C is an end view of the area a-a in Figure 1B. In Figure 1C, the area near the weld metal is shown in detail, and hatching is omitted except for the weld metal area to avoid making the drawing cluttered. 【0022】 In the configuration shown in Figure 1A, the hot-stamped molded body 100 is a hat-shaped member and includes a first steel plate member 101, a second steel plate member 102, and a weld metal 103 that joins the first steel plate member 101 and the second steel plate member 102. The first steel plate member 101 has a pair of flange portions 101a, a pair of wall portions 101b rising from the pair of flange portions 101a, and a top plate portion 101c connecting the pair of wall portions 101b. Similarly, the second steel plate member 102 has a pair of flange portions 102a (only one flange portion 102a is shown in Figure 1A), a pair of wall portions 102b rising from the pair of flange portions 102a (only one wall portion 102b is shown in Figure 1A), and a top plate portion 102c connecting the pair of wall portions 102b. 【0023】 The hot-stamped molded body 100 is obtained by hot-stamping a tailor-welded blank (TWB), which is made by butt-welding two steel plates of different thicknesses together using laser welding. 【0024】However, it is preferable that the hot-stamped product is a tailored blank (TB) formed by welding together multiple steel plates and then hot-stamping it. In this specification, TB includes not only the butt-welded TWB described above, but also the overlap-welded TWB and patchwork blank (PB) described later. In this specification, an overlap-welded TWB is defined as a product in which multiple steel plates are welded together in a state where they overlap and protrude from each other when viewed from the thickness direction, and a PB is defined as a product in which multiple steel plates are welded together in a state where the largest of the multiple steel plates includes the other steel plates (hereinafter also referred to as "patchwork welding"). 【0025】 As shown in Figure 1C, the hot-stamped molded body 100 has a first region 11 and a second region 12. The first region 11 is the thickest part of the hot-stamped molded body 100. In the examples shown in Figures 1A to C, the top plate portion 101c of the first steel plate member 101 becomes the first region 11. In the example shown in Figure 1C, the first region 11 is made of one steel plate 11a, but it may be made of two or more steel plates laminated together. There are no particular restrictions on the thickness of the first region 11, but it is preferably 1.2 to 3.0 mm, and more preferably 1.6 to 2.6 mm. In the example shown in Figure 1C, the thickness of the first region 11 refers to the thickness of the steel plate 11a, but if two or more steel plates are laminated together, the sum of the thicknesses of all the steel plates becomes the thickness of the first region 11. 【0026】The second region 12 is connected to the first region 11 by the weld metal 13. That is, the first region 11 and the weld metal 13 are directly connected, and the second region 12 and the weld metal 13 are directly connected. The second region 12 may also be directly connected to the first region 11. In the example shown in Figure 1C, the second region 12 is made of one steel plate 12a, but it may be made of two or more steel plates laminated together. There are no particular restrictions on the thickness of the second region 12, but it is preferably 0.8 to 2.0 mm, and more preferably 1.0 to 1.4 mm. In the example shown in Figure 1C, the thickness of the second region 12 refers to the thickness of the steel plate 12a, but if two or more steel plates are laminated together, the sum of the thicknesses of all the steel plates becomes the thickness of the second region 12. 【0027】 In the hot-stamped molded body 100, the standard hardness of the steel plate 11a constituting the first region 11 and the steel plate 12a constituting the second region 12 is both 400 HV1 or higher, and the absolute value of the difference between them is 200 HV1 or less. If there are multiple steel plates in the first region 11 and / or the second region 12, the standard hardness of all of these multiple steel plates is 400 HV1 or higher, and the absolute value of the difference between the standard hardnesses of the steel plates is 200 HV1 or less. Preferably, the standard hardness of steel plate 11a and steel plate 12a is 450 HV1 or higher. Furthermore, preferably, the absolute value of the difference between the standard hardnesses of steel plate 11a and steel plate 12a is 150 HV1 or less. While there is no need to set an upper limit on the standard hardness, the standard hardness of steel plate 11a is preferably 700 HV or less, more preferably 600 HV or less, and the standard hardness of steel plate 12a is preferably 600 HV or less, more preferably 500 HV or less. There is no need to set a lower limit on the absolute value of the difference between the standard hardnesses of steel plate 11a and steel plate 12a; it is 0 HV or greater. 【0028】 Here, the reference hardness refers to the hardness measured by the following method. First, one circular disc-shaped test piece with a diameter of 8 mm is cut from the steel plate 11a constituting the first region 11 and the steel plate 12a constituting the second region 12, and a cylindrical test specimen is made using the cut test pieces. Figure 2 is a schematic diagram showing the cylindrical test specimen made using the test pieces. 【0029】As shown in Figure 2, the test specimen 500 comprises a test piece 50 and a pair of steel dummy materials 60 provided to sandwich the test piece 50. If scale, a decarburized layer, a plating solid solution layer, etc., are formed on the surface layer of the steel plate 11a (test piece 50), the test piece 50 from which the surface layer has been removed by polishing or the like shall be used. In addition, a thermocouple for temperature measurement shall be attached to the side of the test piece 50. 【0030】 Each pair of dummy materials 60 has a disc or cylindrical shape with a diameter of 8 mm. The steel type (chemical composition) of the dummy materials 60 may be the same as or different from that of the test piece 50. However, if the steel type of the dummy materials 60 is different from that of the test piece 50, a steel with a C content of 0.1 to 0.5% by mass and a total content of Cr, Mo, V, W, and Nb of less than 2.0% is used as the material for the dummy materials 60. The thickness of the pair of dummy materials 60 is approximately equal to that of the test specimen 500. In this embodiment, the thickness of the pair of dummy materials 60 is adjusted so that the height of the test specimen 500 is 12.0 mm. 【0031】 The obtained test specimen 500 is subjected to a heat treatment using a hot working reproduction test apparatus (Thermo-mechanical simulator: Thermecaster-Z, manufactured by Fuji Denpa Koki Co., Ltd.). The specimen is heated to 900°C at a heating rate of 5°C / s and held for 2 minutes, then immediately cooled to Ms+10°C at a cooling rate of 50°C / s, and subsequently cooled to 25°C at a cooling rate of 20°C / s. After the heat treatment, the test specimen 50 is cut in the thickness direction along its diameter. On the resulting cut surface, the Vickers hardness is measured at three locations at 0.5 mm intervals with a test force of 9.807 N (1 kgf), with the measurement center being at the 1 / 4 thickness position and 1 / 4 of the diameter from the outer circumference. The average of these measured values ​​is taken as the reference hardness. 【0032】 As mentioned above, the test force for Vickers hardness testing should be 9.807 N (1 kgf), and other conditions should conform to JIS Z 2244-1:2020. Furthermore, "HV1" refers to the "hardness symbol" when a Vickers hardness test is performed with a test force of 9.807 N (1 kgf) (see JIS Z 2244-1:2020). 【0033】 Further, in the hot stamp formed body 100, the quenching degree at the 1 / 4 thickness position x of the steel sheet 11a constituting the first region 11 １ (hereinafter simply referred to as "quenching degree of the steel sheet 11a") is 0.90 to 1.10. The quenching degree of the steel sheet 11a is preferably 0.95 to 1.05. Further, in a cross section orthogonal to the direction in which the boundary 14a extends as shown in FIG. 1C, at the 1 / 4 thickness position y of the steel sheet 12a constituting the second region 12, at a position 10 mm away from the boundary 14a with the weld metal 13 in the direction orthogonal to the thickness direction １－１０ the quenching degree (hereinafter simply referred to as "quenching degree of the steel sheet 12a at the 10 mm position") is 0.90 to 1.10, and at the 1 / 4 thickness position y of the steel sheet 12a at a position 60 mm away from the boundary 14a in the direction orthogonal to the thickness direction １－６０ the quenching degree (hereinafter simply referred to as "quenching degree of the steel sheet 12a at the 60 mm position") is 0.40 to 0.80. The quenching degree of the steel sheet 12a at the 10 mm position is preferably 0.95 to 1.05, the quenching degree of the steel sheet 12a at the 60 mm position is preferably 0.70 or less, and more preferably 0.60 or less. In the following description, the quenching degree at the 1 / 4 thickness position of the steel sheet 12a at a position Y mm away from the boundary 14a in the direction orthogonal to the thickness direction (where Y is an arbitrary natural number) is simply referred to as "quenching degree of the steel sheet 12a at the Y mm position", etc. 【0034】 Here, the quenching degree means a value obtained by dividing the Vickers hardness measured at a predetermined position by the reference hardness measured by the above method at the said predetermined position. That is, the value obtained by dividing the Vickers hardness measured at the position x １ by the reference hardness of the steel sheet 11a is the quenching degree of the steel sheet 11a. Also, the value obtained by dividing the Vickers hardness measured at the position y １－１０ by the reference hardness of the steel sheet 12a is the quenching degree of the steel sheet 12a at the 10 mm position. Similarly, the value obtained by dividing the Vickers hardness measured at the position y １－６０ by the reference hardness of the steel sheet 12a is the quenching degree of the steel sheet 12a at the 60 mm position. 【0035】 Incidentally, the position x １ , the position y １－１０ , and the position y １－６０The Vickers hardness measured is taken at three points at 0.5 mm intervals in a direction perpendicular to the thickness direction, centered on each position, in a cross-section parallel to the thickness direction and perpendicular to the direction in which the boundary 14a extends, as shown in Figure 1C. The test force for Vickers hardness measurement is 9.807 N (1 kgf), and other conditions should conform to JIS Z 2244-1:2020. The average of these measured values ​​is taken as the Vickers hardness. Position x １ The measurement shall be taken at a position 60 mm away from the boundary 14b between the steel plate 11a and the weld metal 13 in a direction perpendicular to the thickness direction. However, if the length of the first region 11 in the direction perpendicular to the thickness direction is 120 mm or less, the measurement shall be taken at the center position in the direction perpendicular to the thickness direction of the first region 11. 【0036】 position x １ The Vickers hardness measured is preferably 450 to 600 HV1, and position y １－１０ The Vickers hardness measured is preferably 450 to 600 HV1, and position y １－６０ The Vickers hardness measured is preferably between 180 and 350 HV1. 【0037】 The relatively high degree of hardening of steel plate 11a, while the relatively low degree of hardening of steel plate 12a at the 60 mm position, means that the strength in the first region 11 is higher than that in the second region 12. However, by making the degree of hardening of steel plate 12a at the 10 mm position the same as that of steel plate 11a, a distance difference is created between the point of abrupt change in plate thickness and the point of abrupt change in strength. This makes it possible to suppress deformation concentration in the hot-stamped molded body. 【0038】There are no particular restrictions on the degree of hardening in the region between the 10 mm and 60 mm positions of the steel plate 12a. However, from the viewpoint of mitigating abrupt changes in strength, it is preferable that the degree of hardening in the region between the 10 mm and 60 mm positions of the steel plate 12a is lower than the degree of hardening at the 10 mm position of the steel plate 12a and higher than the degree of hardening at the 60 mm position of the steel plate 12a. Here, the degree of hardening in the region between the 10 mm and 60 mm positions of the steel plate 12a means the average value of the degree of hardening at nine positions at 5 mm intervals from the 15 mm to the 55 mm position of the steel plate 12a. 【0039】 There are no particular restrictions on the hardness of the weld metal 13, but the standard hardness of the weld metal 13 is HVM. Ｓ (HV1), the lower of the standard hardness values ​​of steel plate 11a and steel plate 12a is set to HVL. Ｓ (HV1) If [HVM Ｓ ≥HVL Ｓ It is preferable that the following conditions be met: [HVM Ｓ ≥HVL Ｓ It is more preferable to satisfy [HVM] +50]. Ｓ ≥HVL Ｓ It is even more preferable to satisfy [+100]. If there are multiple steel plates in the first region 11 and / or the second region 12, the lowest reference hardness shall be adopted. 【0040】 On the other hand, the higher of the standard hardness values ​​of steel plate 11a and steel plate 12a is set to HVH Ｓ (HV1) If [HVM Ｓ ≤HVH Ｓ It is preferable that the condition [+200] is satisfied, [HVM Ｓ ≤HVH Ｓ It is more preferable to satisfy [HVM] +150]. Ｓ ≤HVH Ｓ It is even more preferable to satisfy [+100]. If there are multiple steel plates in the first region 11 and / or the second region 12, the highest standard hardness shall be adopted. 【0041】 Furthermore, the Vickers hardness of the weld metal 13 is HVM (HV1), and the position y １－６０ The Vickers hardness measured by HVy６０ If (HV1), then [HVM ≥ HVy ６０ It is preferable that the following conditions be satisfied: [HVM ≥ HVy ６０ It is more preferable to satisfy [HVM ≥ HVy] +50. ６０ It is even more preferable to satisfy [+100]. If there are multiple steel plates in the second region 12, the lowest Vickers hardness will be adopted. 【0042】 On the other hand, position x １ Vickers hardness and position y measured １－１０ The higher of the two Vickers hardness values ​​measured by HVxy １０ If (HV1), then [HVM ≤ HVxy １０ It is preferable that the condition [HVM ≤ HVxy] is satisfied, and [HVM ≤ HVxy] １０ It is more preferable to satisfy [HVM ≤ HVxy] + 150 １０ It is even more preferable to satisfy [+100]. If there are multiple steel plates in the first region 11 and / or the second region 12, the highest Vickers hardness will be adopted. 【0043】When measuring the reference hardness of the weld metal 13, one circular disc-shaped test piece with a diameter of 8 mm is cut out so that the weld metal 13 is included in the central part. At this time, the test piece is cut out so that the upper and lower surfaces of the test piece substantially coincide with the upper and lower surfaces of the steel plate 12a. In the example shown in Figure 1C, the thickness of the test piece cut out from the weld metal 13 is substantially the same as the thickness of the test piece cut out from the steel plate 12a as described above. Using the cut test piece, a cylindrical test specimen 500 as shown in Figure 2 is prepared. Then, heat treatment is performed using a hot working reproduction test apparatus under the same conditions as described above, and after heat treatment, the test piece 50 is cut in the thickness direction along the diameter. On the obtained cut surface, the Vickers hardness is measured at three locations at 0.5 mm intervals with a test force of 9.807 N (1 kgf) along the direction of the diameter, with the measurement center being at the 1 / 4 thickness position and at the 1 / 2 diameter position from the outer circumference. If the indentation (indentation) formed when measuring the Vickers hardness overlaps with a blowhole in the weld metal 13, a test specimen is taken from a different location, and the same test is repeated to measure the Vickers hardness at the three locations mentioned above. If measurements are taken at three locations at 0.5 mm intervals without overlapping with a blowhole, the average of these measurements is taken as the reference hardness of the weld metal 13. 【0044】 Furthermore, the Vickers hardness of the weld metal 13 is at the center of the weld metal 13 in the direction perpendicular to the thickness direction, in a cross-section perpendicular to the direction in which the boundary 14a extends, as shown in Figure 1C, and at a position w that coincides with the 1 / 4 thickness position of the steel plate 12a in the thickness direction. １ This is the Vickers hardness measured at position w. More specifically, position w １ Using the measurement center as the measurement point, the Vickers hardness is measured at three locations at 0.5 mm intervals along a direction perpendicular to the thickness direction, with a test force of 9.807 N (1 kgf). If the indentation (indentation) formed when measuring the Vickers hardness overlaps with a blowhole in the weld metal 13, the Vickers hardness is measured again at the same three locations in a different cross-section. If measurements are taken at three locations at 0.5 mm intervals without overlapping with a blowhole, the average of these measurements is taken as the Vickers hardness of the weld metal 13. 【0045】In the present invention, the hot-stamped molded body may be plated. In this specification, the "thickness" mentioned above refers to the thickness of the base material portion obtained by subtracting the plating thickness from the total thickness. The plating thickness is measured by a high-frequency glow discharge surface analyzer (GDS). The specific measurement method is described below. 【0046】 Three arbitrary measurement points are determined at locations 10 mm and 60 mm away from the boundary 14a between the steel plates 11a and 12a of the hot-stamped molded body 100. At each measurement point, the concentrations of the elements Fe, Mn, Zn, Si, Al, O, Cr, Ni, Mg, Cu, and Sn are measured while sputtering from the surface of the plating layer. 【0047】 The content of each element is analyzed in the depth direction to determine the depth at which the Fe concentration first exceeds 90% by mass. The average depth at each measurement point is then calculated, and this average value is taken as the plating thickness at each location. If the Fe concentration does not exceed 90% by mass at the depth analyzed in a single GDS measurement, i.e., if the plating layer is thicker than the measured depth, then 80-90% of the plating layer corresponding to the previously measured depth is removed by polishing at an arbitrary location within the same area, different from the previously measured location. The depth of the plating layer removed by polishing is determined from the change in plate thickness before and after polishing, and then a new GDS analysis is performed on the surface after polishing. The plating thickness is determined by combining the results of the first and subsequent measurements. 【0048】 For GDS measurement, for example, a Marcus-type high-frequency glow discharge emission spectrometer GD-Profiler2 (manufactured by HORIBA) is used. In this case, for example, the discharge conditions are 35W, the Ar pressure during measurement is 600Pa, the discharge area is 4mm in diameter, the electrode distance is 0.15 to 0.25mm, and the measurement pitch in the plate thickness direction is 0.01 to 0.05μm. 【0049】Figure 3A is a schematic perspective view of a hot-stamped molded body according to another embodiment of the present invention. In the figure, the hatched areas indicate the weld metal. Figure 3B is a top view of a hot-stamped molded body according to another embodiment of the present invention, and the dashed lines in the hatched areas indicate that the weld metal is not actually visible from the top. Figure 3C is an end view of the b-b section of Figure 3B, and Figure 3D is an end view of the c-c section of Figure 3B. In Figures 3C and 3D, the area near the weld metal is shown in magnified view, and hatching is omitted except for the weld metal area to avoid making the drawings cluttered. 【0050】 In the configuration shown in Figure 3A, the hot-stamped molded body 200 is a hat-shaped member and includes a first steel plate member 201, a second steel plate member 202, and a weld metal 203 that joins the first steel plate member 201 and the second steel plate member 202. The first steel plate member 201 has a pair of flange portions 201a, a pair of wall portions 201b rising from the pair of flange portions 201a, and a top plate portion 201c connecting the pair of wall portions 201b. Similarly, the second steel plate member 202 has a pair of flange portions 202a (only one flange portion 202a is shown in Figure 3A), a pair of wall portions 202b rising from the pair of flange portions 202a (only one wall portion 202b is shown in Figure 3A), and a top plate portion 202c connecting the pair of wall portions 202b. 【0051】 The hot-stamped molded body 200 is obtained by hot-stamping a TWB, which is formed by overlapping and welding two steel plates together using spot welding. 【0052】As shown in Figure 3C, the hot-stamped molded body 200 has a first region 21 and a second region 22. The first region 21 is the thickest part of the hot-stamped molded body 200. In the examples shown in Figures 3A to D, the first region 21 is the portion where the top plate portion 201c of the first steel plate member 201 and the top plate portion 202c of the second steel plate member 202 are overlapped. In the examples shown in Figures 3C and D, the first region 21 is made up of two steel plates 21a and 21b stacked together, but it may be made up of three or more steel plates stacked together. There are no particular restrictions on the thickness of the first region 21, but it is preferably 2.0 to 5.0 mm, and more preferably 2.6 to 4.0 mm. In the examples shown in Figures 3C and D, the thickness of the first region 21 means the total thickness of the steel plates 21a and 21b. 【0053】 The second region 22 is directly connected to the first region 21. In the example shown in Figures 3C and 3D, the second region 22 consists of a single steel plate 22a, but it may also consist of two or more steel plates laminated together. There are no particular restrictions on the thickness of the second region 22, but it is preferably 0.8 to 2.0 mm, and more preferably 1.0 to 1.4 mm. In the example shown in Figures 3C and 3D, the thickness of the second region 22 refers to the thickness of the steel plate 22a, but if two or more steel plates are laminated together, the sum of the thicknesses of all the steel plates becomes the thickness of the second region 22. 【0054】 In the hot-stamped molded body 200, the reference hardness of the steel plates 21a and 21b constituting the first region 21 and the steel plate 22a constituting the second region 22 is all 400 HV1 or higher, and the absolute value of the difference between them is 200 HV1 or lower. Since steel plate 21b and steel plate 22a are the same steel plate, their reference hardnesses are the same. 【0055】The standard hardness of steel plates 21a, 21b, and 22a is preferably 450 HV1 or higher. Furthermore, the absolute difference between the standard hardnesses of steel plates 21a, 21b, and 22a is preferably 150 HV1 or less. While there is no upper limit to the standard hardness, the standard hardness of steel plates 21a and 21b is preferably 700 HV or less, more preferably 600 HV or less, and the standard hardness of steel plate 22a is preferably 600 HV or less, more preferably 500 HV or less. There is no lower limit to the absolute difference between the standard hardnesses of steel plates 21a, 21b, and 22a; it is 0 HV or higher. 【0056】 The first region 21 includes weld metal 23 formed by spot welding, but the reference hardness of the steel plates 21a and 21b is measured in the portion excluding the weld metal 23. 【0057】 Furthermore, in the hot-stamped molded body 200, the position x of the steel plate 21a constituting the first region 21 is 1 / 4 of the thickness. ２－１ and the position x at 1 / 4 of the thickness of the steel plate 21b ２－２ The degree of hardening at position x (hereinafter simply referred to as "degree of hardening of steel plate 21a" and "degree of hardening of steel plate 21b") is 0.90 to 1.10. Preferably, the degree of hardening of steel plates 21a and 21b is 0.95 to 1.05. Here, position x ２－１ and position x ２－２ As shown in Figure 3D, the position is set at a point 1 / 4 of the thickness from the surfaces in contact with each other. Note that the first region 21 includes weld metal 23 formed by spot welding, but as shown in Figures 3B and 3D, the hardness of the steel plates 21a and 21b is measured in a cross-section that does not pass through the weld metal 23. Furthermore, when three or more steel plates are stacked, for steel plates where both the top and bottom surfaces are in contact with other steel plates, the reference hardness and hardness are measured at a position 1 / 4 of the thickness from both the top and bottom surfaces, and the average value is adopted. Position x ２－１ and position x ２－２The measurement shall be taken at a position 60 mm away from the boundary 24 between the steel plates 21a and 21b constituting the first region 21 and the steel plate 22a constituting the second region 22, in a direction perpendicular to the thickness direction. However, if the length of the first region 21 in the direction perpendicular to the thickness direction is 120 mm or less, the measurement shall be taken at the center position in the direction perpendicular to the thickness direction of the first region 21. 【0058】 Furthermore, at the point where the steel plate 22a constituting the second region 22 is 10 mm away from the boundary 24, at the position y of 1 / 4 of the thickness ２－１０ The degree of hardening at the point (hereinafter simply referred to as "degree of hardening at the 10 mm position of the steel plate 22a") is 0.90 to 1.10, and the thickness 1 / 4 position y at a location 60 mm away from the boundary 24 is 0.90 to 1.10. ２－６０ The degree of hardening at the 60 mm position of the steel plate 22a (hereinafter simply referred to as "degree of hardening at the 60 mm position of the steel plate 22a") is 0.40 to 0.80. Preferably, the degree of hardening at the 10 mm position of the steel plate 22a is 0.95 to 1.05, and preferably the degree of hardening at the 60 mm position of the steel plate 22a is 0.70 or less, and more preferably 0.60 or less. 【0059】 position x ２－１ and position x ２－２ The Vickers hardness measured is preferably 450 to 600 HV1, and position y ２－１０ The Vickers hardness measured is preferably 450 to 600 HV1, and position y ２－６０ The Vickers hardness measured is preferably between 180 and 350 HV1. 【0060】 There are no particular restrictions on the degree of hardening in the region between the 10 mm and 60 mm positions of the steel plate 22a. However, from the viewpoint of mitigating abrupt changes in strength, it is preferable that the degree of hardening in the region between the 10 mm and 60 mm positions of the steel plate 22a is lower than the degree of hardening at the 10 mm position of the steel plate 22a and higher than the degree of hardening at the 60 mm position of the steel plate 22a. Here, the degree of hardening in the region between the 10 mm and 60 mm positions of the steel plate 22a means the average value of the degree of hardening at nine positions at 5 mm intervals from the 15 mm to the 55 mm position of the steel plate 22a. 【0061】There are no particular restrictions on the hardness of the weld metal 23, but the standard hardness of the weld metal 23 is HVM. Ｓ (HV1), the lowest standard hardness of the standard hardness of steel plates 21a, 21b and steel plate 22a is HVL Ｓ (HV1) If [HVM Ｓ ≥HVL Ｓ It is preferable that the following conditions be met: [HVM Ｓ ≥HVL Ｓ It is more preferable to satisfy [HVM] +50]. Ｓ ≥HVL Ｓ It is even more preferable to satisfy [+100]. 【0062】 On the other hand, the highest standard hardness of the steel plates 21a, 21b and 22a is HVH Ｓ (HV1) If [HVM Ｓ ≤HVH Ｓ It is preferable that the condition [+200] is satisfied, [HVM Ｓ ≤HVH Ｓ It is more preferable to satisfy [HVM] +150]. Ｓ ≤HVH Ｓ It is even more preferable to satisfy [+100]. 【0063】 Furthermore, the Vickers hardness of the weld metal 23 is HVM (HV1), and the position y ２－６０ The Vickers hardness measured by HVy ６０ If (HV1), then [HVM ≥ HVy ６０ It is preferable that the following conditions be satisfied: [HVM ≥ HVy ６０ It is more preferable to satisfy [HVM ≥ HVy] +50. ６０ It is even more preferable to satisfy [+100]. If there are multiple steel plates in the second region 22, the lowest Vickers hardness will be adopted. 【0064】 On the other hand, position x ２－１ Vickers hardness measured at position x ２－２ Vickers hardness and position y are measured at ２－１０ The highest Vickers hardness measured is HVxy. １０ If (HV1), then [HVM ≤ HVxy １０It is preferable that the condition [HVM ≤ HVxy] is satisfied, and [HVM ≤ HVxy] １０ It is more preferable to satisfy [HVM ≤ HVxy] + 150 １０ It is even more preferable to satisfy [+100]. 【0065】 Furthermore, as shown in the example in Figure 3C, when the weld metal 23 is formed by spot welding, the reference hardness and Vickers hardness of the weld metal 23 shall be measured using the procedure described above. However, the measurement position shall not be at the position where 1 / 4 of the thickness of the steel plate 21b is reached, but rather at the position where 1 / 2 of the maximum thickness of the weld metal 23 within the steel plate 21b is reached. ２ As shown in Figures 3B and 3C, the reference hardness and Vickers hardness of the weld metal 23 are measured in a cross-section passing through the center of the weld metal 23, and the center of the weld metal 23 is the center of the approximate circle of the spot weld indentation observed when viewed from the thickness direction. 【0066】 Figure 4A is a schematic perspective view of a hot-stamped molded body according to another embodiment of the present invention. In the figure, the hatched areas indicate the weld metal. Figure 4B is a top view of a hot-stamped molded body according to another embodiment of the present invention, and the dashed lines in the hatched areas indicate that the weld metal is not actually visible from the top. Figure 4C is an end view of the d-d section of Figure 4B, and Figure 4D is an end view of the e-e section of Figure 4B. In Figures 4C and 4D, the area near the weld metal is shown in magnified view, and hatching is omitted except for the weld metal area to avoid making the drawings cluttered. 【0067】In the configuration shown in Figure 4A, the hot-stamped molded body 300 is a hat-shaped member and includes a first steel plate member 301, a second steel plate member 302, and a weld metal 303 that joins the first steel plate member 301 and the second steel plate member 302. The first steel plate member 301 has a pair of flange portions 301a, a pair of wall portions 301b rising from the pair of flange portions 301a (only one wall portion 301b is shown in Figure 4A), and a top plate portion 301c that connects the pair of wall portions 301b. Similarly, the second steel plate member 302 has a pair of flange portions 302a (only one flange portion 302a is shown in Figure 4A), a pair of wall portions 302b rising from the pair of flange portions 302a, and a top plate portion 302c that connects the pair of wall portions 302b. As shown in Figure 4A, the first steel plate member 301 is welded to overlap a part of the second steel plate member 302. 【0068】 The hot-stamped molded body 300 is formed by hot-stamping a PB, which is made by spot-welding two steel plates. 【0069】 As shown in Figure 4C, the hot-stamped molded body 300 has a first region 31 and a second region 32. The first region 31 is the thickest part of the hot-stamped molded body 300. In the examples shown in Figures 4C and 4D, the first region 31 is made up of two steel plates 31a and 31b laminated together, but it may be made up of three or more steel plates laminated together. There are no particular restrictions on the thickness of the first region 31, but it is preferably 1.2 to 3.0 mm, and more preferably 1.6 to 2.6 mm. In the examples shown in Figures 4C and 4D, the thickness of the first region 31 refers to the total thickness of the steel plates 31a and 31b. 【0070】 The second region 32 is directly connected to the first region 31. In the example shown in Figures 4C and 4D, the second region 32 consists of a single steel plate 32a, but it may also consist of two or more steel plates laminated together. There are no particular restrictions on the thickness of the second region 32, but it is preferably 0.8 to 2.0 mm, and more preferably 1.0 to 1.4 mm. In the example shown in Figures 4C and 4D, the thickness of the second region 32 refers to the thickness of the steel plate 32a, but if two or more steel plates are laminated together, the sum of the thicknesses of all the steel plates becomes the thickness of the second region 32. 【0071】 In the hot-stamped molded body 300, the reference hardness of the steel plates 31a and 31b constituting the first region 31 and the steel plate 32a constituting the second region 32 is all 400 HV1 or higher, and the absolute value of the difference between them is 200 HV1 or lower. Since steel plate 31b and steel plate 32a are the same steel plate, their reference hardnesses are the same. 【0072】 The standard hardness of steel plates 31a, 31b, and 32a is preferably 450 HV1 or higher. Furthermore, the absolute difference between the standard hardnesses of steel plates 31a, 31b, and 32a is preferably 150 HV1 or less. While there is no upper limit to the standard hardness, the standard hardness of steel plates 31a and 31b is preferably 700 HV or less, more preferably 600 HV or less, and the standard hardness of steel plate 32a is preferably 600 HV or less, more preferably 500 HV or less. There is no lower limit to the absolute difference between the standard hardnesses of steel plates 31a, 31b, and 32a; it is 0 HV or higher. 【0073】 The first region 31 includes weld metal 33 formed by spot welding, but the reference hardness of the steel plates 31a and 31b is measured in the portion excluding the weld metal 33. 【0074】 Furthermore, in the hot-stamped molded body 300, the position x of the steel plate 31a constituting the first region 31 is 1 / 4 of the thickness. ３－１ and the position x at 1 / 4 of the thickness of the steel plate 31b ３－２ The degree of hardening at position x (hereinafter simply referred to as "degree of hardening of steel plate 31a" and "degree of hardening of steel plate 31b") is 0.90 to 1.10. Preferably, the degree of hardening of steel plates 31a and 31b is 0.95 to 1.05. Here, position x ３－１ and position x ３－２As shown in FIG. 4D, it is set at the position of 1 / 4 of the thickness from the surfaces in contact with each other. Although the first region 31 includes the welded metal 33 formed by spot welding, as shown in FIGS. 4B and 4D, the hardening degree of the steel plates 31a and 31b is to be measured in a cross section that does not pass through the welded metal 33. Further, when three or more steel plates are laminated, for the steel plate where both the upper surface and the lower surface are in contact with other steel plates, the reference hardness and the hardening degree are measured at the positions of 1 / 4 of the thickness of each of the upper surface and the lower surface, and the average value thereof is to be adopted. Position x ３－１ and position x ３－２ are to be measured at a position 60 mm away from the boundary 34 between the steel plates 31a and 31b constituting the first region 31 and the steel plate 32a constituting the second region 32 in a direction orthogonal to the thickness direction. However, when the length in the direction orthogonal to the thickness direction of the first region 31 is 120 mm or less, it is to be measured at the central position in the direction orthogonal to the thickness direction of the first region 31. 【0075】 Further, for the steel plate 32a constituting the second region 32, the 1 / 4 thickness position y ３－１０ of the portion 10 mm away from the boundary 34 (hereinafter, simply referred to as "the hardening degree of the steel plate 32a at the 10 mm position").) is 0.90 to 1.10, and the 1 / 4 thickness position y ３－６０ of the portion 60 mm away from the boundary 34 (hereinafter, simply referred to as "the hardening degree of the steel plate 32a at the 60 mm position").) is 0.40 to 0.80. The hardening degree of the steel plate 32a at the 10 mm position is preferably 0.95 to 1.05, and the hardening degree of the steel plate 32a at the 60 mm position is preferably 0.70 or less, and more preferably 0.60 or less. 【0076】 Position x ３－１ and position x ３－２ The Vickers hardness measured at is preferably 450 to 600 HV1, and the Vickers hardness measured at position y ３－１０ is preferably 450 to 600 HV1, and the Vickers hardness measured at position y ３－６０ is preferably 180 to 350 HV1. 【0077】There are no particular restrictions on the hardening degree in the region between the 10 mm position and the 60 mm position of the steel plate 32a. However, from the perspective of alleviating a sharp change in strength, it is preferable that the hardening degree in the region between the 10 mm position and the 60 mm position of the steel plate 32a is lower than the hardening degree at the 10 mm position of the steel plate 32a and higher than the hardening degree at the 60 mm position of the steel plate 32a. Here, the hardening degree in the region between the 10 mm position and the 60 mm position of the steel plate 32a means the average value of the hardening degrees at nine positions at 5 mm intervals from the 15 mm position to the 55 mm position of the steel plate 32a. 【0078】 There are no particular restrictions on the hardness of the weld metal 33, but the reference hardness of the weld metal 33 is HV_M Ｓ (HV1), and the lowest reference hardness among the reference hardnesses of the steel plates 31a, 31b, and 32a is HV_L Ｓ (HV1). When this is the case, it is preferable to satisfy [HV_M Ｓ ≥ HV_L Ｓ , more preferably to satisfy [HV_M Ｓ ≥ HV_L Ｓ + 50], and even more preferably to satisfy [HV_M Ｓ ≥ HV_L Ｓ + 100]. 【0079】 On the other hand, when the highest reference hardness among the reference hardnesses of the steel plates 31a, 31b, and 32a is HV_H Ｓ (HV1), it is preferable to satisfy [HV_M Ｓ ≤ HV_H Ｓ + 200], more preferably to satisfy [HV_M Ｓ ≤ HV_H Ｓ + 150], and even more preferably to satisfy [HV_M Ｓ ≤ HV_H Ｓ + 100]. 【0080】 Also, when the Vickers hardness of the weld metal 33 is HV_M (HV1) and the Vickers hardness measured at the position y ３－６０ is HV_y ６０ (HV1), it is preferable to satisfy [HV_M ≥ HV_y ６０ , more preferably to satisfy [HV_M ≥ HV_y ６０ + 50], and even more preferably to satisfy [HV_M ≥ HV_y６０ It is even more preferable to satisfy [+100]. If there are multiple steel plates in the second region 32, the lowest Vickers hardness will be adopted. 【0081】 On the other hand, position x ３－１ Vickers hardness measured at position x ３－２ Vickers hardness and position y are measured at ３－１０ The highest Vickers hardness measured is HVxy. １０ If (HV1), then [HVM ≤ HVxy １０ It is preferable that the condition [HVM ≤ HVxy] is satisfied, and [HVM ≤ HVxy] １０ It is more preferable to satisfy [HVM ≤ HVxy] + 150 １０ It is even more preferable to satisfy [+100]. 【0082】 Furthermore, as shown in the example in Figure 4C, when the weld metal 33 is formed by spot welding, the reference hardness and Vickers hardness of the weld metal 33 shall be measured using the procedure described above. However, the measurement position shall not be at the position where 1 / 4 of the thickness of the steel plate 31b is reached, but rather at the position where 1 / 2 of the maximum thickness of the weld metal 33 within the steel plate 31b is reached. ３ As shown in Figures 4B and 4C, the reference hardness and Vickers hardness of the weld metal 33 are measured in a cross-section passing through the center of the weld metal 33, and the center of the weld metal 33 is the center of the approximate circle of the spot weld indentation observed when viewed from the thickness direction. 【0083】2. Mechanical Properties In the hot-stamped molded article according to this embodiment, it is preferable that the product of the Vickers hardness and the maximum bending angle at a point 60 mm away from the boundary of the steel plate constituting the second region with either the first region or the weld metal, in a direction perpendicular to the direction of extension of the boundary and the thickness direction, is 33,000 HV 1 / ° or more. By improving the balance between hardness and bending deformability, when the hot-stamped molded article is used in an automobile part, not only is deformation concentration easier to suppress, but collision safety is also improved. It is more preferable that the product of the Vickers hardness and the maximum bending angle is 34,000 HV 1 / ° or more, and even more preferable that it is 35,000 HV 1 / ° or more. Since a higher product of the Vickers hardness and the maximum bending angle is preferable, there is no need to set an upper limit, but the practical upper limit is 80,000 HV 1 / °. 【0084】 Here, the maximum bending angle can be determined by the VDA bending test (VDA 238-100:2017), which is standardized by the German Association of the Automotive Industry (VDA). Figure 5A is a plan view of the test specimen S before the test, which is used in the bending test. Figure 5B is a schematic diagram to explain the bending test, showing the test specimen S, punch P, and roll R. 【0085】 As shown in Figure 5B, this VDA bending test is performed by placing a test specimen S on two rolls R, R and pressing it between the rolls R, R with a punch P having a tip radius of 0.4 mm to deform the test specimen S into a V shape. The closest distance between the two rolls R, R is 2 × plate thickness (mm) + 0.5 (mm). As shown in Figure 5B, the test specimen S is deformed to become V-shaped when viewed along the width direction. The ridge line L created by the bending of the test specimen S at this time is a line along the width direction of the test specimen S. 【0086】 The load and stroke of punch P are measured at this time. The load on punch P, which increased at the start of the test, decreases rapidly as fracture occurs at the bending peak of the test piece S. The maximum bending angle is calculated from the stroke when the load decreases by 60 N from the maximum load. 【0087】The formula for calculating the maximum bending angle from the stroke is the formula described in Annex D of VDA238-100 mentioned above. If no fracture occurs in the test specimen S even with a stroke of 14 mm, the value obtained from the formula for calculating the maximum bending angle from the bending angle at a stroke of 14 mm shall be taken as the maximum bending angle of the test specimen S. 【0088】 The length of the test specimen S is 60 mm, the width is 30 mm, and the thickness is the original thickness of the steel plate constituting the second region. The test specimen S is taken from the second region such that the direction in which the boundary with either the first region or the weld metal, whichever is closer, extends is the width direction of the test specimen S, and a position 30 mm away from this boundary coincides with the ridge line L. 【0089】 3. Chemical Composition The chemical composition of the hot-stamped molded article according to this embodiment is not particularly limited. In the hot-stamped molded article according to this embodiment, it is preferable that the steel sheet constituting the first region and the steel sheet constituting the second region have, for example, the chemical composition shown below. The reasons for limiting each element are as follows. In the following description, "%" for content means "mass%". 【0090】 C: 0.10-0.60% C is an element that improves the strength of hot-stamped molded articles. Therefore, a C content of 0.10% or more is preferable. More preferably, the C content is greater than 0.10%, 0.15% or more, 0.18% or more, 0.20% or more, or 0.25% or more. From the viewpoint of weldability, a C content of 0.60% or less is preferable. More preferably, the C content is 0.50% or less, 0.40% or less, 0.38% or less, 0.37% or less, 0.35% or less, or 0.30% or less. A C content of 0.10-0.50%, 0.10-0.40%, greater than 0.10% and 0.38% or less, 0.15-0.37%, 0.18-0.36%, 0.20-0.35%, or 0.25-0.30% is preferable. 【0091】Si: 0.01 to 2.00% Si is an element that improves the strength of hot-stamped molded articles through solid solution strengthening. Therefore, a Si content of 0.01% or more is preferable. More preferably, the Si content is 0.05% or more, 0.10% or more, 0.20% or more, 0.30% or more, or 0.40% or more. On the other hand, if the Si content exceeds 2.00%, it may not be possible to obtain the desired degree of hardening. Therefore, a Si content of 2.00% or less is preferable. More preferably, the Si content is 1.80% or less, 1.50% or less, 1.20% or less, 1.00% or less, or 0.80% or less. A Si content of 0.05 to 1.80%, 0.10 to 1.50%, 0.20 to 1.20%, 0.30 to 1.00%, or 0.40 to 0.80% is preferable. 【0092】 Mn: 0.10 to 3.00% Mn is an element that enhances the hardenability of steel and contributes to improving its strength. Therefore, the Mn content is preferably 0.10% or more. The Mn content is more preferably 0.20% or more, 0.50% or more, 1.00% or more, 1.30% or more, or 1.50% or more. On the other hand, if the Mn content exceeds 3.00%, Mn segregation may become significant. Therefore, the Mn content is preferably 3.00% or less. The Mn content is more preferably 2.80% or less, 2.50% or less, 2.30% or less, or 2.00% or less. The Mn content is preferably 0.20 to 2.80%, 0.50 to 2.50%, 1.00 to 2.30%, 1.30 to 2.00%, or 1.50 to 2.00%. 【0093】 P: 0.050% or less. P is an impurity element and may cause a decrease in weldability. Therefore, it is preferable that the P content be 0.050% or less. More preferably, the P content is 0.030% or less, 0.020% or less, or 0.010% or less. There is no particular need to limit the lower limit of the P content, and it may be 0%. However, if the P content is reduced excessively, the cost of removing P will increase significantly, which is economically undesirable. Therefore, the P content may be greater than 0%, or 0.0001% or more. 【0094】S: 0.0200% or less. S is an impurity element and may cause a decrease in weldability. Therefore, it is preferable that the S content be 0.0200% or less. More preferably, the S content is 0.0180% or less, 0.0150% or less, 0.0100% or less, 0.0060% or less, or 0.0040% or less. There is no particular need to limit the lower limit of the S content, and it may be 0%. However, if the S content is reduced excessively, the cost of S removal will increase significantly, which is economically undesirable. Therefore, the S content may be greater than 0%, or 0.0001% or more. 【0095】 N: 0.0200% or less. N is an impurity element and may cause a decrease in weldability. Therefore, it is preferable that the N content be 0.0200% or less. More preferably, the N content is 0.0180% or less, 0.0150% or less, 0.0100% or less, 0.0060% or less, or 0.0040% or less. There is no particular need to limit the lower limit of the N content, and it may be 0%. However, if the N content is reduced excessively, the cost of removing N will increase significantly, which is economically undesirable. Therefore, the N content may be greater than 0%, or 0.0001% or more. 【0096】 O: 0.100% or less. If oxygen is present in large amounts in steel, it may cause a decrease in weldability. Therefore, it is preferable that the oxygen content be 0.100% or less. It is more preferable that the oxygen content be 0.070% or less, 0.050% or less, 0.030% or less, 0.010% or less, or 0.005% or less. There is no particular need to limit the lower limit of the oxygen content, and it may be 0%. However, from the viewpoint of reducing refining costs, the oxygen content may be greater than 0%, 0.0001% or more, or 0.0005% or more. 【0097】Al: 0.001 to 0.100% Al is an element that deoxidizes molten steel and makes the steel sound. Therefore, it is preferable that the Al content be 0.001% or more. More preferably, the Al content is 0.005% or more, 0.010% or more, 0.015% or more, 0.020% or more, or 0.025% or more. On the other hand, if the Al content exceeds 0.100%, the effect becomes saturated, so it is preferable that the Al content be 0.100% or less. More preferably, the Al content is 0.080% or less, 0.060% or less, 0.040% or less, 0.020% or less, or 0.010% or less. The Al content is preferably 0.005 to 0.080%, 0.010 to 0.070%, 0.015 to 0.060%, 0.020 to 0.050%, or 0.025 to 0.040%. Furthermore, the Al content is preferably 0.001 to 0.020% or 0.001 to 0.010%. 【0098】 Cr: 0.01 to 1.00% Cr is an element that improves the hardenability of steel. Therefore, a Cr content of 0.01% or more is preferable. More preferably, the Cr content is 0.03% or more, 0.05% or more, 0.10% or more, or 0.15% or more. On the other hand, if the Cr content exceeds 1.00%, the above effect becomes saturated, so a Cr content of 1.00% or less is preferable. More preferably, the Cr content is 0.80% or less, 0.60% or less, 0.50% or less, or 0.40% or less. A Cr content of 0.03 to 0.80%, 0.05 to 0.60%, 0.10 to 0.50%, or 0.15 to 0.40% is preferable. 【0099】 The basic chemical composition of the hot-stamped molded article according to the embodiment of the present invention is as described above. Furthermore, the hot-stamped molded article may, if necessary, contain at least one of the following optional elements in place of a portion of the remaining Fe. The optional elements will be described in detail below. 【0100】Nb: 0-0.200% Nb is an element that forms carbonitrides in steel, improving the strength of hot-stamped molded articles through precipitation strengthening. The Nb content may be 0.0005% or more, but to reliably obtain this effect, it is preferable that the Nb content be 0.001% or more or 0.002% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Nb content be 0.200% or less. The Nb content may be 0.180% or less, 0.150% or less, 0.100% or less, 0.050% or less, or 0.010% or less. The Nb content is preferably 0.0005-0.180%, 0.001-0.150%, 0.002-0.100%, 0.003-0.050%, or 0.004-0.010%. 【0101】 Ti: 0 to 0.200% Ti is an element that forms carbonitrides in steel, improving the strength of hot-stamped molded articles through precipitation strengthening. The Ti content may be 0.001% or more, but to reliably obtain this effect, it is preferable that the Ti content be 0.010% or more or 0.020% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Ti content be 0.200% or less. The Ti content may be 0.180% or less, 0.150% or less, 0.100% or less, 0.070% or less, or 0.040% or less. The Ti content is preferably 0.001 to 0.180%, 0.005 to 0.150%, 0.010 to 0.100%, 0.015 to 0.070%, or 0.020 to 0.040%. 【0102】 Mo: 0-1.00% Mo is an element that improves the hardenability of steel. The Mo content may be 0.001% or more, but to reliably obtain this effect, it is preferable that the Mo content be 0.003% or more or 0.005% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Mo content be 1.00% or less. The Mo content may be 0.80% or less, 0.60% or less, 0.50% or less, 0.30% or less, or 0.10% or less. The Mo content is preferably 0.001-0.80%, 0.002-0.60%, 0.003-0.50%, 0.004-0.30%, or 0.005-0.10%. 【0103】 B: 0 to 0.0100% B is an element that improves the hardenability of steel. The B content may be 0.0001% or more, but to reliably obtain this effect, it is preferable that the B content be 0.0005% or more or 0.0010% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the B content be 0.0100% or less. The B content may be 0.0080% or less, 0.0060% or less, 0.0050% or less, 0.0030% or less, or 0.0020% or less. The B content is preferably 0.0001 to 0.0080%, 0.0003 to 0.0060%, 0.0005 to 0.0050%, 0.0007 to 0.0030%, or 0.0010 to 0.0020%. 【0104】 Co: 0-4.00% Co is an element that improves the strength of hot-stamped molded articles through solid solution strengthening. The Co content may be 0.001% or more, but to reliably obtain this effect, it is preferable that the Co content be 0.01% or more or 0.05% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Co content be 4.00% or less. The Co content may be 3.00% or less, 2.00% or less, 1.00% or less, 0.50% or less, or 0.10% or less. The Co content is preferably 0.001-3.00%, 0.005-2.00%, 0.01-1.00%, 0.03-0.50%, or 0.05-0.10%. 【0105】Ni: 0-2.00% Ni has the effect of increasing the strength of the hot-stamped molded product by solid-solubilizing into the austenite grains during heating in the hot-stamping molding process. The Ni content may be 0.001% or more, but to reliably obtain this effect, it is preferable that the Ni content be 0.01% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Ni content be 2.00% or less. The Ni content may be 1.80% or less, 1.60% or less, 1.40% or less, 1.20% or less, 1.00% or less, 0.50% or less, or 0.10% or less. The Ni content is preferably 0.001 to 1.80%, 0.005 to 1.60%, 0.01 to 1.40%, 0.02 to 1.20%, 0.03 to 1.00%, 0.04 to 0.50%, or 0.05 to 0.10%. 【0106】 Cu: 0-1.00% Cu has the effect of increasing the strength of the hot-stamped molded product by solid-solubilizing into the austenite grains during heating in the hot-stamping molding process. The Cu content may be 0.001% or more, but to reliably obtain this effect, it is preferable that the Cu content be 0.01% or more or 0.05% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Cu content be 1.00% or less. The Cu content may be 0.80% or less, 0.60% or less, 0.50% or less, 0.30% or less, or 0.10% or less. The Cu content is preferably 0.001-0.80%, 0.005-0.60%, 0.01-0.50%, 0.03-0.30%, or 0.05-0.10%. 【0107】V: 0-1.00% V has the effect of improving the strength of hot-stamped molded articles by forming carbonitrides in the steel and strengthening by precipitation. The V content may be 0.001% or more, but to reliably obtain this effect, it is preferable that the V content be 0.01% or more or 0.05% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the V content be 1.00% or less. The V content may be 0.80% or less, 0.60% or less, 0.50% or less, 0.30% or less, or 0.10% or less. The V content is preferably 0.001-0.80%, 0.005-0.60%, 0.01-0.50%, 0.03-0.30%, or 0.05-0.10%. 【0108】 W: 0-1.00% W is an element that improves the hardenability of steel. The W content may be 0.001% or more, but to reliably obtain this effect, it is preferable that the W content be 0.005% or more or 0.01% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the W content be 1.00% or less. The W content may be 0.80% or less, 0.60% or less, 0.50% or less, 0.30% or less, or 0.10% or less. The W content is preferably 0.001-0.80%, 0.005-0.60%, 0.01-0.50%, 0.03-0.30%, or 0.05-0.10%. 【0109】 Ca: 0-0.100% Ca is an element that can control the form of sulfides. The Ca content may be 0.0001% or more, but to reliably obtain this effect, it is preferable that the Ca content be 0.0005% or more or 0.0010% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Ca content be 0.100% or less. The Ca content may be 0.080% or less, 0.060% or less, 0.040% or less, 0.020% or less, 0.010% or less or 0.0060% or less. The Ca content is preferably 0.0001 to 0.080%, 0.0003 to 0.060%, 0.0005 to 0.040%, 0.0007 to 0.020%, 0.0010 to 0.010%, or 0.0015 to 0.0060%. 【0110】Mg: 0-0.100% Mg is an element that can control the form of sulfides. The Mg content may be 0.0001% or more, but to reliably obtain this effect, it is preferable that the Mg content be 0.0005% or more or 0.0010% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Mg content be 0.100% or less. The Mg content may be 0.080% or less, 0.060% or less, 0.040% or less, 0.020% or less, 0.010% or less or 0.0060% or less. The Mg content is preferably 0.0001 to 0.080%, 0.0003 to 0.060%, 0.0005 to 0.040%, 0.0007 to 0.020%, 0.0010 to 0.010%, or 0.0015 to 0.0060%. 【0111】 REM: 0-0.100% REM is an element that can control the form of sulfides. The REM content may be 0.0001% or more, but to reliably obtain this effect, it is preferable that the REM content be 0.0005% or more or 0.0010% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the REM content be 0.100% or less. The REM content may be 0.080% or less, 0.060% or less, 0.040% or less, 0.020% or less, 0.010% or less or 0.0060% or less. The REM content is preferably 0.0001 to 0.080%, 0.0003 to 0.060%, 0.0005 to 0.040%, 0.0007 to 0.020%, 0.0010 to 0.010%, or 0.0015 to 0.0060%. 【0112】 In this embodiment, "REM" refers to a total of 17 elements including Sc, Y, and lanthanides, and "REM content" refers to the content of one type of REM if there is only one type, or the total content of two or more types if there are two or more types. Furthermore, REM is generally supplied as mischmetal, which is an alloy of multiple types of REM. For this reason, individual elements may be added and included one or more types, or they may be added in the form of mischmetal, for example. 【0113】Sb: 0 to 0.100% Sb is an element that suppresses oxidation of the surface of the base steel sheet. To reliably obtain this effect, it is preferable that the Sb content be 0.001% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Sb content be 0.100% or less. The Sb content may be 0.080% or less, 0.060% or less, 0.050% or less, 0.030% or less, or 0.010% or less. It is preferable that the Sb content be 0.0001 to 0.080%, 0.0005 to 0.060%, 0.001 to 0.050%, 0.003 to 0.030%, or 0.005 to 0.010%. 【0114】 Zr: 0 to 0.100% Zr is an element that suppresses oxidation of the surface of the base steel sheet. To reliably obtain this effect, it is preferable that the Zr content be 0.001% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Zr content be 0.100% or less. The Zr content may be 0.080% or less, 0.060% or less, 0.050% or less, 0.030% or less, or 0.010% or less. It is preferable that the Zr content be 0.0001 to 0.080%, 0.0005 to 0.060%, 0.001 to 0.050%, 0.003 to 0.030%, or 0.005 to 0.010%. 【0115】 Sn: 0-1.00% Sn is an element that suppresses oxidation of the surface of the base steel sheet. To reliably obtain this effect, it is preferable that the Sn content be 0.001% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the Sn content be 1.00% or less. The Sn content may be 0.800% or less, 0.500% or less, 0.200% or less, 0.100% or less, 0.050% or less, or 0.010% or less. It is preferable that the Sn content be 0.0001-0.800%, 0.0005-0.500%, 0.001-0.200%, 0.002-0.100%, 0.003-0.050%, or 0.005-0.010%. 【0116】As: 0-0.100% As has the effect of increasing the strength of hot-stamped molded articles. To reliably obtain this effect, it is preferable that the As content be 0.001% or more. On the other hand, even if a large amount is included, the above effect will saturate, so it is preferable that the As content be 0.100% or less. The As content may be 0.080% or less, 0.050% or less, 0.020% or less, 0.010% or less, or 0.005% or less. The As content is preferably 0.001-0.080%, 0.002-0.050%, 0.003-0.020%, 0.004-0.015%, or 0.005-0.010%. 【0117】 In the chemical composition of the hot-stamped molded article according to this embodiment, the remainder of the elements other than those mentioned above consists of Fe and impurities. Impurities are components that are mixed in during the industrial production of hot-stamped molded articles due to various factors in the manufacturing process, including raw materials such as ore and scrap. 【0118】 The chemical composition of the hot-stamped molded body described above can be measured using general analytical methods. For example, it can be measured using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). C and S can be measured using the combustion-infrared absorption method, N using the inert gas fusion-thermal conductivity method, and O using the inert gas fusion-non-dispersive infrared absorption method. If the hot-stamped molded body has a plating layer on its surface, the plating layer should be removed by mechanical grinding before the chemical composition analysis can be performed. 【0119】 4. Applications The applications of the hot-stamped molded articles according to this embodiment are not particularly limited, but they can be suitably used as automotive parts. Examples of automotive parts include center pillars, front side members, rear side members, and side sills. 【0120】 5. Manufacturing Method An example of a manufacturing method for a hot-stamped molded article according to this embodiment will be described. 【0121】First, a steel sheet (blank) to be used as the material for the hot-stamped molded body is manufactured. Molten steel having the above-mentioned chemical composition is produced, and a slab is manufactured using this molten steel. As the slab to be subjected to hot rolling, a slab manufactured by continuous casting or a thin slab caster can be used. The above method for manufacturing steel sheets is suitable for processes such as continuous casting-direct rolling (CC-DR), in which hot rolling is performed immediately after casting. 【0122】 It is preferable to heat the slab at 1100°C or higher. Heating the slab at temperatures below 1100°C leads to a decrease in the finish rolling temperature, which tends to result in higher strength during finish rolling. As a result, rolling may become difficult or lead to defects in the shape of the steel sheet after rolling, so it is preferable to heat the slab at 1100°C or higher. There is no need to set an upper limit on the slab heating temperature, but from the viewpoint of suppressing excessive scale formation, it is preferable to keep it at 1300°C or lower. 【0123】 The finish rolling completion temperature is preferably 800°C or higher. If the finish rolling completion temperature falls below 800°C, the rolling load will increase, which may make rolling difficult or lead to defects in the shape of the steel sheet after rolling. Therefore, the lower limit of the finish rolling completion temperature is preferably 800°C. There is no particular need to set an upper limit for the finish rolling completion temperature, but if the finish rolling completion temperature is set too high, the slab heating temperature must be set too high in order to maintain that temperature. Therefore, the upper limit of the finish rolling completion temperature is preferably 1100°C. After the finish rolling is completed, the average cooling rate up to the winding temperature, which will be described later, is preferably 10 to 100°C / s. 【0124】The winding temperature is preferably 700°C or lower. If the winding temperature exceeds 700°C, the thickness of the oxide formed on the surface of the steel sheet may increase excessively, potentially reducing its pickling properties. If cold rolling is to be performed afterward, the lower limit of the winding temperature is preferably 400°C. If the winding temperature is below 400°C, the strength of the hot-rolled steel sheet increases drastically, making it prone to sheet fracture and shape defects during cold rolling; therefore, the lower limit of the winding temperature is preferably 400°C. However, if the wound hot-rolled steel sheet is to be softened by heating it in a box-type annealing furnace or continuous annealing equipment, it is acceptable to wind it at a low temperature of less than 400°C. In addition, rough-rolled sheets may be joined together during hot rolling and continuous finish rolling may be performed. Furthermore, the rough-rolled sheets may be wound up once. 【0125】 The above hot-rolled steel sheet may be pickled, and the hot-rolled steel sheet after pickling may be cold-rolled to produce a cold-rolled steel sheet. When cold-rolling is performed, the reduction ratio can be, for example, 20 to 80%. The pickling treatment can be carried out by immersing the sheet for 30 seconds or more in an aqueous solution containing an inhibitor and an acid concentration of 3 to 20% by mass at a temperature of 80°C or higher but less than 100°C. Furthermore, the above hot-rolled or cold-rolled steel sheet may be annealed to produce a hot-rolled annealed sheet or a cold-rolled annealed sheet. Annealing is carried out by passing the sheet through a continuous annealing line, and the annealing temperature can be, for example, in the range of 700 to 950°C. 【0126】 After obtaining the various steel plates described above, a TB (Turret Barrel) is manufactured by performing butt welding using laser welding, arc welding, plasma welding, etc., or overlap welding using laser welding, spot welding, arc welding, seam welding, plasma welding, etc., on two or more steel plates. 【0127】Before obtaining TB from the steel sheet, plating may be applied. While not particularly limited, examples of applicable plating include hot-dip galvanizing, alloyed hot-dip galvanizing, electroplating, Zn-Ni plating (electroalloyed zinc plating), Sn plating, Al-Si plating, alloyed electroplating, hot-dip zinc-aluminum alloy plating, hot-dip zinc-aluminum-magnesium alloy plating, hot-dip zinc-aluminum-magnesium-Si alloy plating, and zinc-deposited Al plating. Furthermore, the plating process can be carried out by passing the sheet through a continuous line. 【0128】 Next, hot stamping is performed on the TB. In this process, the TB is heated, and then press-formed and hardened. In hot stamping, for example, when producing the hot-stamped molded body 100 shown in Figures 1A to C, press-formed and hardened can be performed using a divisible mold with the structure shown in Figures 6A and 6B. 【0129】 Figures 6A and 6B are schematic diagrams illustrating a method for manufacturing a hot-stamped molded article according to one embodiment of the present invention, and show the end face of the a-a portion of Figure 1B. Figure 6A shows the state immediately after press forming, and Figure 6B shows the state of dividing the mold. As shown in Figure 6A, first, two pairs of molds 15a, b, c, and d are lowered to the bottom dead center to perform press forming with respect to the TB to achieve a predetermined shape, and the molds are cooled. As shown in Figures 6A and 6B, the molds 15a and 15b are in contact with the steel plate 11a as well as the steel plate 12a. However, a gap is provided between the right end of the portion where the mold 15a and the steel plate 11a are in contact and the left end of the portion where the mold 15a and the steel plate 12a are in contact. This is intended to suppress damage to the molding surface of the mold and fracture of the blank. 【0130】Subsequently, the pair of molds 15a and 15b are cooled to a temperature below the Mf point without demolding to perform quenching. As a result, the areas of the steel plate 11a constituting the first region 11 and the steel plate 12a constituting the second region 12, including the 10 mm position, are rapidly cooled, and the degree of quenching of the steel plate 11a and the degree of quenching of the steel plate 12a at the 10 mm position are within the range of 0.90 to 1.10. The time for which the molds 15a and 15b are held at the bottom dead center is 20 s or more, preferably 25 s or more. On the other hand, considering productivity, the time for which the molds 15a and 15b are held at the bottom dead center is preferably 100 s or less, and more preferably 60 s or less. 【0131】 In order to achieve a hardening degree of 0.90 or higher at the 10 mm position of the steel plate 12a, it is preferable to set the contact length T between the mold 15a and the steel plate 12a in a direction perpendicular to the thickness direction to 10 mm or more, and more preferably to 15 mm or more. On the other hand, in order to achieve a hardening degree of 0.80 or lower at the 60 mm position of the steel plate 12a, it is preferable to set the contact length T to 40 mm or less, and more preferably to 35 mm or less. 【0132】 Furthermore, considering press formability, it is preferable to set the gap length G in the direction perpendicular to the thickness direction between the right end of the contact area between the die 15a and the steel plate 11a and the left end of the contact area between the die 15a and the steel plate 12a to 10 mm or more, and more preferably 15 mm or more. On the other hand, in order to set the hardening degree of the steel plate 12a at the 10 mm position to 0.90 or more, it is preferable to set the gap length G to 30 mm or less, and more preferably 25 mm or less. Similarly, in order to set the hardening degree of the steel plate 12a at the 60 mm position to 0.80 or less, the sum of the contact length T and the gap length G should be 50 mm or less, and more preferably 40 mm or less. Also, it is preferable to set the sum of the contact length T and the gap length G to 20 mm or more, and more preferably 30 mm or more. 【0133】Regarding the cooling rate, for example, the average cooling rate from the molding start temperature to the Ms point can be set to 50°C / s or more, and the average cooling rate from the Ms point to the Mf point can be set to 10°C / s or more. There is no need to set an upper limit on the cooling rate, but from the viewpoint of manufacturing equipment capacity, it is preferable to set the average cooling rate from the molding start temperature to the Ms point to 2000°C / s or less, and the average cooling rate from the Ms point to the Mf point to 1800°C / s or less. Furthermore, after demolding the pair of molds 15a and 15b in the temperature range below the Mf point, they can be allowed to cool to room temperature at an average cooling rate of, for example, 2 to 5°C / s. In this specification, room temperature means 25°C. 【0134】 On the other hand, for the portion of the steel plate 12a including the 60 mm position, after cooling the mold to 500-600°C, the pair of molds 15c and d are immediately released, and then allowed to cool. The time for which the molds 15c and d are held at the bottom dead center is 5 seconds or less, preferably 3 seconds or less. There is no lower limit to the time for which they are held at the bottom dead center; it may be 0 seconds or more. This ensures that the degree of hardening of the steel plate 12a at the 60 mm position is within the range of 0.40 to 0.80. The cooling rate can be, for example, 50°C / s or more from the molding start temperature to the release temperature. There is no upper limit to the cooling rate, but from the viewpoint of manufacturing equipment capacity, it is preferable that the average cooling rate from the molding start temperature to the release temperature be 2000°C / s or less. After the release of the pair of molds 15c and d, they can be allowed to cool to room temperature at an average cooling rate of, for example, 2-5°C / s. 【0135】 The heating of TB is done by Ac ３ The process should be carried out at a temperature above 2°C and held for at least 10 seconds. There are no particular restrictions on other conditions, but for example, an average heating rate of 2 to 200°C / s is recommended. ３ Ac above points ３ After heating to a temperature of 120°C or lower, the temperature can be maintained in that range for 10 to 120 seconds. After removing the TB from the furnace, molding is started. At this time, the temperature at the start of molding should be 700°C or higher. During the period from when the TB is removed from the furnace until molding begins, it is air-cooled at an average cooling rate of 10 to 20°C / s. 【0136】 Here, in the present invention, Ac３ The points Ac, Ms, and Mf shall be determined based on the following equations (I) to (III). ３ (°C) = 850 + 10 × (C + N) × Mn + 350 × Nb + 250 × Ti + 40 × B + 10 × Cr + 100 × Mo ... (I) Ms (°C) = 550 - 361 × C - 39 × Mn - 35 × V - 20 × Cr - 17 × Ni - 10 × Cu - 5 × (Mo + W) + 15 × Co + 30 × Al ... (II) Mf (°C) = 410.5 - 407.3 × C - 7.3 × Si - 37.8 × Mn - 20.5 × Cu - 19.5 × Ni - 19.8 × Cr - 4.5 × Mo ... (III) However, the element symbols in the above formulas represent the content (mass %) of each element. 【0137】 The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples. 【0138】 Molten steel (steel grades a to m) having the chemical composition shown in Table 1 was cast by continuous casting to produce slabs. After heating these slabs to a temperature of 1100°C or higher, rough rolling, finish rolling, cooling, and coiling were performed under the conditions shown in Table 2 to obtain hot-rolled steel sheets with a thickness of 2.6 mm. Subsequently, the hot-rolled steel sheets were further cold-rolled at the cold rolling rates shown in Table 2 to obtain cold-rolled steel sheets. 【0139】 【0140】 【0141】 Next, steel plates A and B, having the steel type, plate thickness, and reference hardness shown in Table 3, were prepared and welded together using the method shown in Table 3 to produce various types of TBs. In Table 3, "laser" means that butt welding was performed by laser welding (see Figures 1A-C), and "patch" means that patchwork welding was performed by spot welding (see Figures 4A-D). Subsequently, the reference hardness of the weld metal was also measured. The measurement method for the reference hardness of each steel plate and weld metal is as described above. 【0142】 【0143】Next, three hat-shaped hot-stamped bodies exhibiting the shapes shown in Figure 1A or Figure 4A were produced by hot-stamping each of the obtained TBs under the conditions shown in Table 4. For hot-stamping, an apparatus with two pairs of molds shown in Figures 6A and 6B was used. Table 4 shows the heating conditions before hot-stamping (heating temperature and holding time), as well as the contact length T between the mold 15a and the steel plate B, the gap length G between the right end of the mold 15a that contacts the steel plate A and the left end that contacts the steel plate B, and the time during which the molds 15a, b and 15c, d are held at their respective bottom dead centers (bottom dead center holding time). 【0144】 Subsequently, using one of the hot-stamped molded bodies produced, the Vickers hardness and degree of hardness of the steel plates constituting the first and second regions, as well as the weld metal, were measured using the method described above. For the second region, the maximum bending angle was also measured using the method described above. The results are shown in Table 5. Note that in Table 5, Vickers hardness is simply referred to as "hardness." 【0145】 Furthermore, in Table 5, in the case of a hat-shaped hot-stamped molded body exhibiting the shape shown in Figure 1A, the position at 1 / 4 of the thickness of the steel plate A constituting the first region, 60 mm away from the boundary with the weld metal, is x １ , the 1 / 4 thickness positions of the steel plate B constituting the second region, located 10 mm and 60 mm away from the boundary with the weld metal, are respectively y １０ and y ６０ It is written as follows: The above x １ , y １０ and y ６０ These are shown in Figure 1C, x １ , y １－１０ and y １－６０ It corresponds to the following. In addition, in the case of a hat-shaped hot-stamped molded body exhibiting the shape shown in Figure 4A, the thickness 1 / 4 position of steel plates A and B constituting the first region, 60 mm away from the boundary with the second region, is set to x １ and x ２ , the 1 / 4 thickness positions of the steel plate B constituting the second region, located 10 mm and 60 mm away from the weld metal, respectively, are y １０ and y ６０It is written as follows: The above x １ , y １０ and y ６０ These are shown in Figure 4D, x ３－１ , y ３－１０ and y ３－６０ It supports this. 【0146】 【0147】 【0148】 Subsequently, for each test number, the remaining two hot-stamped molded bodies were joined so that their flange portions met, forming two hat members. The joining was performed by spot welding the flange portions at 25 mm intervals. Next, 9 mm thick plate material was joined to both ends of the resulting hat members in the longitudinal direction by arc welding. Then, with the steel plate A side facing downwards and the longitudinal direction of both hat members facing vertically, an axial crush test was performed using a crush test machine, crushing the material vertically at a speed of 1 mm / s by 80 mm. After that, the presence or absence of fracture was visually confirmed. The results are shown in Table 5. 【0149】 As shown in Table 5, in test numbers 1 to 3 and 7 to 10, which satisfy the provisions of the present invention, no fracture occurred in the axial crushing test. In contrast, in comparative example test numbers 4 to 6, deformation concentration occurred near the boundary of the second region in the axial crushing test, resulting in fracture. Specifically, in test number 4, the absolute value of the difference in reference hardness between steel plate A and steel plate B was excessive, so deformation concentration could not be suppressed. Also, in test number 5, the mold 15a and steel plate B were not in contact, so y １０ The degree of hardening decreased, and deformation concentration occurred near the boundary between steel plate A and steel plate B. Furthermore, in test number 6, because molds 15c and d were not immediately released, y ６０ The degree of hardening was excessive, resulting in deformation concentration in steel plate B. 【0150】 According to the present invention, when there are two or more parts with different plate thicknesses within a single component, it is possible to obtain a hot-stamped molded body and an automotive part containing the same that can suppress deformation concentration in parts where the plate thickness changes abruptly.

Claims

1. A hot-stamped molded body comprising one or more steel plates, having a first region which is the thickest part of the hot-stamped molded body, and a second region comprising one or more steel plates and connected to the first region directly or by weld metal, wherein a test piece taken from a predetermined position is subjected to a heat treatment in which it is heated to 900°C at a heating rate of 5°C / s and held for 2 min, immediately cooled to Ms+10°C at a cooling rate of 50°C / s, and then cooled to 25°C at a cooling rate of 20°C / s, and the Vickers hardness measured at the predetermined position is taken as the reference hardness at the predetermined position, and the value obtained by dividing the Vickers hardness measured at the predetermined position by the reference hardness is taken as the degree of hardness at the predetermined position, wherein the reference hardness of the steel plate constituting the first region and the steel plate constituting the second region are both 400 HV1 or higher, and the absolute value of the difference between them is 200 HV1 or lower, A hot-stamped molded body wherein the degree of hardening at the 1 / 4 thickness position of the steel plate constituting the first region is 0.90 to 1.10, the degree of hardening at the 1 / 4 thickness position of the steel plate constituting the second region at a point 10 mm away from the boundary with the steel plate constituting the first region or the weld metal, whichever is closer, is 0.90 to 1.10, and the degree of hardening at the 1 / 4 thickness position of the steel plate constituting the second region at a point 60 mm away from the boundary with the steel plate constituting the first region or the weld metal, whichever is closer, is 0.40 to 0.

80.

2. The hot-stamped molded article according to claim 1, wherein the product of the Vickers hardness and the maximum bending angle at a point 60 mm away from the boundary of the steel plate constituting the second region with the first region or the weld metal, whichever is closer, is 33,000 HV 1· degree or more.

3. The chemical composition of the steel plate constituting the first region and the steel plate constituting the second region is, in mass%, C: 0.10 to 0.60%, Si: 0.01 to 2.00%, Mn: 0.10 to 3.00%, P: 0.050% or less, S: 0.0200% or less, N: 0.0200% or less, O: 0.100% or less, Al: 0.001 to 0.100%, Cr: 0.01 to 1.00%, Nb: 0 to 0.200%, Ti: 0 to 0.200%, Mo: 0 to 1.00%, B: 0 to 0.0100%, Co: 0 to 4.00%, Ni: 0 to 2.00%, Cu: 0 to 1.00%, V: 0 to 1.00%, The hot-stamped molded article according to claim 1, wherein the composition is: W: 0-1.00%, Ca: 0-0.100%, Mg: 0-0.100%, REM: 0-0.100%, Sb: 0-0.100%, Zr: 0-0.100%, Sn: 0-1.00%, As: 0-0.100%, the remainder being Fe and impurities.

4. The chemical composition of the steel plate constituting the first region and the steel plate constituting the second region is, in mass%, C: 0.10 to 0.60%, Si: 0.01 to 2.00%, Mn: 0.10 to 3.00%, P: 0.050% or less, S: 0.0200% or less, N: 0.0200% or less, O: 0.100% or less, Al: 0.001 to 0.100%, Cr: 0.01 to 1.00%, Nb: 0 to 0.200%, Ti: 0 to 0.200%, Mo: 0 to 1.00%, B: 0 to 0.0100%, Co: 0 to 4.00%, Ni: 0 to 2.00%, Cu: 0 to 1.00%, V: 0 to 1.00%, The hot-stamped molded article according to claim 2, wherein the composition is: W: 0-1.00%, Ca: 0-0.100%, Mg: 0-0.100%, REM: 0-0.100%, Sb: 0-0.100%, Zr: 0-0.100%, Sn: 0-1.00%, As: 0-0.100%, the remainder being Fe and impurities.

5. An automotive part comprising a hot-stamped molded body according to any one of claims 1 to 4.

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