US 12,392,017 B2
Hot-stamping formed body
Yuri Toda, Tokyo (JP); Shinichiro Tabata, Tokyo (JP); Kodai Murasawa, Tokyo (JP); Daisuke Maeda, Tokyo (JP); and Kazuo Hikida, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/781,231
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Jan. 8, 2021, PCT No. PCT/JP2021/000432
§ 371(c)(1), (2) Date May 31, 2022,
PCT Pub. No. WO2021/141103, PCT Pub. Date Jul. 15, 2021.
Claims priority of application No. 2020-002407 (JP), filed on Jan. 9, 2020.
Prior Publication US 2023/0002874 A1, Jan. 5, 2023
Int. Cl. C22C 38/38 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/10 (2006.01); C22C 38/16 (2006.01); C22C 38/22 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01)
CPC C22C 38/38 (2013.01) [C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/02 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01); C22C 38/10 (2013.01); C22C 38/16 (2013.01); C22C 38/22 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01)] 3 Claims
 
1. A hot-stamping formed body comprising, as a chemical composition, by mass %:
C: 0.30% to 0.50%;
Si: 0.50% to 3.00%;
Mn: 0.50% to 3.00%;
Al: 0.0002% to 2.000%;
P: 0.100% or less;
S: 0.1000% or less;
N: 0.0100% or less;
Nb: 0% to 0.150%;
Ti: 0% to 0.150%;
Co: 0% to 2.00%;
Mo: 0% to 1.00%;
Cr: 0% to 1.00%;
Cu: 0% to 1.00%;
V: 0% to 1.00%;
W: 0% to 1.00%;
Ni: 0% to 3.00%;
Mg: 0% to 1.00%;
Zr: 0% to 1.00%;
Sb: 0% to 1.00%;
Ca: 0% to 0.10%;
REM: 0% to 0.30%;
B: 0% to 0.0100%; and
a remainder consisting of Fe and impurities; and
microstructure which includes residual austenite of which an area ratio is 5% or more and less than 10%, bainite and tempered martensite of which a total area ratio exceeds 90% and is 95% or less, and a remainder in microstructure of which an area ratio is less than 5%,
among grain boundaries of crystal grains of the bainite and the tempered martensite, a ratio of a length of a grain boundary having a rotation angle in a range of 55° to 75° to a total length of a grain boundary having a rotation angle in a range of 4° to 12°, a grain boundary having a rotation angle in a range of 49° to 54°, and the grain boundary having a rotation angle in a range of 55° to 75° to the <011> direction as a rotation axis is 30% or more,
wherein a tensile strength of the hot-stamping formed body is 1500 MPa or more.