US 12,227,817 B2
Steel
Shinichiro Tabata, Tokyo (JP); Kazuhisa Kusumi, Tokyo (JP); and Yuki Suzuki, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 18/036,253
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Jan. 19, 2022, PCT No. PCT/JP2022/001710
§ 371(c)(1), (2) Date May 10, 2023,
PCT Pub. No. WO2022/158469, PCT Pub. Date Jul. 28, 2022.
Claims priority of application No. 2021-006369 (JP), filed on Jan. 19, 2021.
Prior Publication US 2023/0407428 A1, Dec. 21, 2023
Int. Cl. B32B 15/01 (2006.01); C21D 1/18 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 33/04 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/20 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/34 (2006.01); C22C 38/38 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C22C 38/54 (2006.01); C22C 38/60 (2006.01); C23C 2/06 (2006.01); C23C 2/12 (2006.01); C23C 2/40 (2006.01)
CPC C21D 9/46 (2013.01) [B32B 15/013 (2013.01); C21D 1/18 (2013.01); C21D 6/002 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0263 (2013.01); C21D 8/0278 (2013.01); C22C 33/04 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/20 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/34 (2013.01); C22C 38/38 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C22C 38/54 (2013.01); C22C 38/60 (2013.01); C23C 2/06 (2013.01); C23C 2/12 (2013.01); C23C 2/40 (2013.01); C21D 2211/008 (2013.01); C21D 2261/00 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A steel comprising:
a steel sheet substrate; and
a protective film formed on at least a part of a surface of the steel sheet substrate,
wherein a chemical composition of the steel sheet substrate is, by mass %,
C: 0.25% to 0.65%;
Si: 0.05% to 2.00%;
Mn: 0.30% to 3.00%;
P: 0.050% or less;
S: 0.0100% or less;
N: 0.010% or less;
O: 0.010% or less;
Cr: 0.05% to 1.00%;
Cu: 0.10% to 1.00%;
Ti: 0% to 0.10%;
B: 0% to 0.0100%;
Mo: 0% to 1.00%;
Ni: 0% to 1.00%;
Nb: 0% to 0.10%;
V: 0% to 1.00%;
Ca: 0% to 0.010%;
Mg: 0% to 0.010%;
Al: 0% to 1.00%;
Sn: 0% to 1.00%;
W: 0% to 1.00%;
Sb: 0% to 1.00%;
Zr: 0% to 1.00%;
Co: 0% to 1.00%;
REM: 0% to 0.30%; and
a remainder: Fe and an impurities,
in an X-ray analysis in which measurement is carried out using a CuKα radiation, in a case where a peak intensity at a diffraction angle (2θ) position of 36.6±0.5° is regarded as 100%, the protective film has a peak having a peak intensity of more than 250% at a diffraction angle (2θ) position of 35.5±0.5°,
a tensile strength is more than 1,500 MPa, and
a ratio of a maximum Cu content in the protective film to a Cu content in the steel sheet substrate is 1.5 or more.