Hot-stamping formed body

Abstract

This hot-stamping formed body has a predetermined chemical composition, in an interior region, a standard deviation of grain sizes of prior austenite grains of 5.0 μm or less, in a surface layer region, an area ratio of bainite of more than 10%, a maximum value of pole density of a texture of 4.0 or less, and a deboronization index of 0.05 or more.

1 . A hot-stamping formed body comprising, as a chemical composition, by mass %:
 C: more than 0.40% and 0.70% or less;   Si: 0.010% to 3.00%;   Mn: 0.60% to 3.00%;   P: 0.100% or less;   S: 0.0100% or less;   N: 0.0200% or less;   O: 0.0200% or less;   Al: 0.0010% to 0.5000%;   Nb: 0.0010% to 0.100%;   Ti: 0.010% to 0.200%;   Cr: 0.01% to 0.80%;   Mo: 0.0010% to 1.000%;   B: 0.0005% to 0.0200%;   Co: 0% to 4.00%;   Ni: 0% to 3.00%;   Cu: 0% to 3.00%;   V: 0% to 3.00%;   W: 0% to 3.00%;   Ca: 0% to 1.000%;   Mg: 0% to 1.000%;   REM: 0% to 1.000%;   Sb: 0% to 1.000%;   Sn: 0% to 1.000%;   Zr: 0% to 1.000%;   As: 0% to 0.100%; and   a remainder: Fe and impurities,   in an interior region, which is a region between 4/16 depth of a sheet thickness from a surface of the hot-stamping formed body and 5/16 depth of the sheet thickness from the surface,   a standard deviation of grain sizes of prior austenite grains is 5.0 μm or less,   in a surface layer region, which is a region between the surface and 1/25 depth of the sheet thickness from the surface,   an area ratio of bainite is more than 10%,   a maximum value of pole density of a texture is 4.0 or less, and   a deboronization index is 0.05 or more.   
     
     
         2 . The hot-stamping formed body according to  claim 1  comprising, as the chemical composition, by mass %, one or more of:
 Co: 0.01% to 4.00%; 
 Ni: 0.01% to 3.00%; 
 Cu: 0.01% to 3.00%; 
 V: 0.01% to 3.00%; 
 W: 0.01% to 3.00%; 
 Ca: 0.001% to 1.000%; 
 Mg: 0.001% to 1.000%; 
 REM: 0.001% to 1.000%; 
 Sb: 0.001% to 1.000%; 
 Sn: 0.001% to 1.000%; 
 Zr: 0.001% to 1.000%; and 
 As: 0.001% to 0.100%.