	US 12,448,660 B2
	Hot-rolled steel sheet and method for manufacturing same
Jun Ando, Tokyo (JP); Teruki Hayashida, Tokyo (JP); Tatsuo Yokoi, Tokyo (JP); and Akifumi Sakakibara, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/787,857
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Feb. 5, 2021, PCT No. PCT/JP2021/004305 § 371(c)(1), (2) Date Jun. 21, 2022, PCT Pub. No. WO2021/157692, PCT Pub. Date Aug. 12, 2021.
Claims priority of application No. 2020-018844 (JP), filed on Feb. 6, 2020.
Prior Publication US 2023/0041990 A1, Feb. 9, 2023
Int. Cl. C22C 38/02 (2006.01); C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01)

CPC C21D 8/0226 (2013.01) [C21D 8/0284 (2013.01); C21D 9/46 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01)]

20 Claims

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

C: 0.01% to 0.30%;

Si: 0.01% to 3.00%;

Mn: 0.20% to 3.00%;

P: 0.030% or less;

S: 0.030% or less;

Al: 0.001% to 2.000%;

N: 0.0100% or less;

Ni: 0.02% to 0.50%;

Nb: 0% to 0.060%;

V: 0% to 0.20%;

Ti: 0% to 0.20%;

Cu: 0% to 0.20%;

Cr: 0% to 0.20%;

Mo: 0% to 1.00%;

B: 0% to 0.0020%;

W: 0% to 0.50%;

Mg: 0% to 0.010%;

Ca: 0% to 0.0100%;

REM: 0% to 0.0100%;

O: 0% to 0.0100%;

Zr: 0% to 0.500%;

Co: 0% to 0.500%;

Zn: 0% to 0.500%;

Sn: 0% to 0.500%; and

a remainder consisting of Fe and impurities,

wherein among measurement points at which elemental analysis is performed at a measurement pitch of 1 μm using an Electron Probe Micro Analyzer in a region of 250 μm×250 μm on a surface, a percentage of measurement points having a Ni content of 0.5 mass % or more is 10% to 70%.