	US 11,866,800 B2
	Steel sheet and method of manufacturing the same
Hiroyuki Kawata, Tokyo (JP); Kengo Takeda, Tokyo (JP); and Mai Nagano, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/786,988
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Dec. 21, 2020, PCT No. PCT/JP2020/047610 § 371(c)(1), (2) Date Jun. 17, 2022, PCT Pub. No. WO2021/140893, PCT Pub. Date Jul. 15, 2021.
Claims priority of application No. 2020-001529 (JP), filed on Jan. 8, 2020.
Prior Publication US 2023/0047282 A1, Feb. 16, 2023
Int. Cl. C21D 9/46 (2006.01); B32B 15/01 (2006.01); C23C 2/02 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/12 (2006.01); C22C 38/16 (2006.01); C22C 38/28 (2006.01); C23C 2/06 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01)

CPC C21D 9/46 (2013.01) [B32B 15/013 (2013.01); C21D 6/001 (2013.01); C21D 6/002 (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); 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 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/16 (2013.01); C22C 38/28 (2013.01); C23C 2/022 (2022.08); C23C 2/06 (2013.01); C23C 2/28 (2013.01); C23C 2/40 (2013.01); C21D 2211/005 (2013.01); Y10T 428/12799 (2015.01)]

12 Claims

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

C: 0.0003% to 0.0100%;

Si: 0.005% to 1.500%;

Mn: 0.010% to 3.000%;

Al: 0.005% to 1.000%;

P: 0.100% or less;

S: 0.0200% or less;

N: 0.0150% or less;

O: 0.0100% or less;

V: 0% to 0.50%;

Cr: 0% to 1.00%;

Ni: 0% to 1.00%;

Cu: 0% to 1.00%;

Mo: 0% to 1.00%;

W: 0% to 1.00%;

B: 0% to 0.0100%;

Sn: 0% to 1.00%;

Sb: 0% to 0.20%;

one or two or more selected from the group of Ca, Ce, Mg, Zr, La, and REM: 0% to 0.0100% in total;

one or two selected from the group of Ti: 0.010% to 0.100% and Nb: 0.005% to 0.060%; and

a remainder including Fe and impurities,

wherein Expression (1) is satisfied,

a microstructure at a ¼ thickness position from a surface in a sheet thickness direction includes, by vol %, 95% or more ferrite, and 5% or less of a remainder of the microstructure, and the ferrite has a proportion of unrecrystallized ferrite of 5% or less, and

a half width w and an X-ray wavelength λ at a peak of (200) plane of the ferrite satisfy Expression (2),

0.80≤{(Ti/48−N/14)+Nb/93}/(C/12)≤5.00 (1),

w×λ≥0.20 (2),

wherein each of Ti, N, Nb, and C in Expression (1) represents a content by mass % of the element, and when the element is not included, 0 is substituted as the content of the element.