	US 12,221,661 B2
	Steel sheet and method for producing same
Masahiro Kubo, Tokyo (JP); Hiroyuki Kawata, Tokyo (JP); Kenichiro Otsuka, Tokyo (JP); and Masafumi Azuma, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/428,715
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Jan. 7, 2020, PCT No. PCT/JP2020/000126 § 371(c)(1), (2) Date Aug. 5, 2021, PCT Pub. No. WO2020/166231, PCT Pub. Date Aug. 20, 2020.
Claims priority of application No. 2019-025635 (JP), filed on Feb. 15, 2019.
Prior Publication US 2022/0112569 A1, Apr. 14, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C21D 8/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/16 (2006.01); C21D 9/46 (2006.01)

CPC C21D 8/005 (2013.01) [C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/16 (2013.01); C21D 9/46 (2013.01)]

13 Claims

1. A steel sheet comprising, as a chemical composition, by mass %:

C: 0.0015% to 0.0320%;

Mn: 0.20% to 1.50%;

P: 0.010% to 0.100%;

Cr: 0.001% to 0.500%;

Si: 0.200% or less;

S: 0.020% or less;

sol. Al: 0.200% or less;

N: 0.0150% or less;

Mo: 0% to 0.500%;

B: 0% to 0.0100%;

Nb: 0% to 0.200%;

Ti: 0% to 0.200%;

Ni: 0% to 0.200%;

Cu: 0% to 0.100%; and

a remainder including iron and impurities,

wherein a metallographic structure in a surface layer region includes ferrite having a volume fraction of 90% or more, and

in the surface layer region,

an average grain size of the ferrite is 1.0 μm to 15.0 μm, and

a texture in which an X_{ODF{001}/{111}, S}as a ratio of an intensity of {001} orientation to an intensity of {111} orientation in the ferrite is 0.30 or more and less than 3.50 is included.