Hot-stamped product

Abstract

This hot-stamping formed article includes a steel sheet, all or part of the steel sheet has a predetermined chemical composition, at a ¼ depth position of a sheet thickness from a surface of the steel sheet, a microstructure contains, by vol %, more than 90.0% of martensite, the average value of Vickers hardness in a region that is 0.3 mm in a sheet thickness direction and 0.6 mm in a direction orthogonal to the sheet thickness direction is 670 or more, the standard deviation of the Vickers hardness in the region is 20 or less, and the tensile strength is 2300 MPa or more.

1 . A hot-stamped product comprising:
 a steel sheet,   wherein all or part of the steel sheet has a chemical composition of,   by mass %,   C: more than 0.40% and 0.70% or less;   Si: less than 2.00%;   Mn: 0.01% or more and less than 0.50%;   P: 0.200% or less;   S: 0.0200% or less;   sol. Al: 0.001% to 1.000%;   N: 0.0200% or less;   Mo: 0.01% or more and less than 0.50%;   B: 0.0002% to 0.0200%;   Ti: 0% to 0.200%;   Nb: 0% to 0.200%;   V: 0% to 0.200%;   Zr: 0% to 0.200%;   Cr: 0% to 2.00%;   W: 0% to 2.00%;   Cu: 0% to 2.00%;   Ni: 0% to 2.00%;   Ca: 0% to 0.0100%;   Mg: 0% to 0.0100%;   REM: 0% to 0.1000%; and   Bi: 0% to 0.0500%   with a remainder of Fe and impurities,   at a ¼ depth position of a sheet thickness from a surface of the steel sheet,   
       a microstructure contains, by vol %, more than 90.0% of martensite,
 an average value of Vickers hardness in a region that is 0.3 mm in a sheet thickness direction and 0.6 mm in a direction orthogonal to the sheet thickness direction is 670 or more, a standard deviation of the Vickers hardness in the region is 20 or less, and 
 a tensile strength is 2300 MPa or more. 
 
     
     
         2 . The hot-stamped product according to  claim 1 ,
 wherein a yield ratio is 0.65 or more.   
     
     
         3 . A hot-stamped product comprising:
 a steel sheet; and   a plating layer formed on a surface of the steel sheet,   wherein all or part of the steel sheet has a chemical composition of,   by mass %,   C: more than 0.40% and 0.70% or less;   Si: less than 2.00%;   Mn: 0.01% or more and less than 0.50%;   P: 0.200% or less;   S: 0.0200% or less;   sol. Al: 0.001% to 1.000%;   N: 0.0200% or less;   Mo: 0.01% or more and less than 0.50%;   B: 0.0002% to 0.0200%;   Ti: 0% to 0.200%;   Nb: 0% to 0.200%;   V: 0% to 0.200%;   Zr: 0% to 0.200%;   Cr: 0% to 2.00%;   W: 0% to 2.00%;   Cu: 0% to 2.00%;   Ni: 0% to 2.00%;   Ca: 0% to 0.0100%;   Mg: 0% to 0.0100%;   REM: 0% to 0.1000%; and   Bi: 0% to 0.0500%   with a remainder of Fe and impurities,   at a ¼ depth position of a sheet thickness of the steel sheet from an interface between the steel sheet and the plating layer,   a microstructure contains, by vol %, more than 90.0% of martensite,   an average value of Vickers hardness in a region that is 0.3 mm in a sheet thickness direction and 0.6 mm in a direction orthogonal to the sheet thickness direction is 670 or more, a standard deviation of the Vickers hardness in the region is 20 or less, and   a tensile strength is 2300 MPa or more, and a yield ratio is 0.65 or more.   
     
     
         4 . The hot-stamped product according to  claim 1 , comprising, in the chemical composition, by mass %, one or more selected from the group of:
 Ti: 0.001% to 0.200%;   Nb: 0.001% to 0.200%;   V: 0.001% to 0.200%; and   Zr: 0.001% to 0.200%.   
     
     
         5 . The hot-stamped product according to  claim 1 , comprising, in the chemical composition, by mass %, one or more selected from the group consisting of:
 Cr: 0.001% to 2.00%;   W: 0.001% to 2.00%;   Cu: 0.001% to 2.00%; and   Ni: 0.001% to 2.00%.   
     
     
         6 . The hot-stamped product according to  claim 1 , comprising, in the chemical composition, by mass %, one or more selected from the group of:
 Ca: 0.0001% to 0.0100%;   Mg: 0.0001% to 0.0100%; and   REM: 0.0001% to 0.1000%.   
     
     
         7 . The hot-stamped product according to  claim 1 , comprising, in the chemical composition, by mass %:
 Bi: 0.0001% to 0.0500%.   
     
     
         8 . The hot-stamped product according to  claim 3 , comprising, in the chemical composition, by mass %, one or more selected from the group of:
 Ti: 0.001% to 0.200%;   Nb: 0.001% to 0.200%;   V: 0.001% to 0.200%; and   Zr: 0.001% to 0.200%.   
     
     
         9 . The hot-stamped product according to  claim 3 , comprising, in the chemical composition, by mass %, one or more selected from the group of:
 Cr: 0.001% to 2.00%;   W: 0.001% to 2.00%;   Cu: 0.001% to 2.00%; and   Ni: 0.001% to 2.00%.   
     
     
         10 . The hot-stamped product according to  claim 3 , comprising, in the chemical composition, by mass %, one or more selected from the group of:
 Ca: 0.0001% to 0.0100%;   Mg: 0.0001% to 0.0100%; and   REM: 0.0001% to 0.1000%.   
     
     
         11 . The hot-stamped product according to  claim 3 , comprising, in the chemical composition, by mass %:
 Bi: 0.0001% to 0.0500%.