The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Sep. 24, 2024

Filed:

Mar. 25, 2021
Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Lingling Yang, Tokyo, JP;

Yoshiyasu Kawasaki, Tokyo, JP;

Tatsuya Nakagaito, Tokyo, JP;

Shotaro Terashima, Tokyo, JP;

Shunsuke Yamamoto, Tokyo, JP;

Katsuya Hoshino, Tokyo, JP;

Yuki Takeda, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 38/60 (2006.01); B21C 47/02 (2006.01); B32B 15/01 (2006.01); B32B 15/04 (2006.01); B32B 15/18 (2006.01); C21D 1/18 (2006.01); C21D 1/25 (2006.01); C21D 1/76 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C21D 9/46 (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 38/10 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/18 (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 38/30 (2006.01); C22C 38/32 (2006.01); C22C 38/34 (2006.01); C22C 38/38 (2006.01); C22C 38/40 (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 38/52 (2006.01); C22C 38/54 (2006.01); C22C 38/58 (2006.01); C23C 2/02 (2006.01); C23C 2/06 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01); C23C 28/00 (2006.01); C23C 28/02 (2006.01); C23C 30/00 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); B21C 47/02 (2013.01); B32B 15/013 (2013.01); B32B 15/015 (2013.01); B32B 15/04 (2013.01); B32B 15/043 (2013.01); B32B 15/18 (2013.01); C21D 1/185 (2013.01); C21D 1/25 (2013.01); C21D 1/76 (2013.01); C21D 6/001 (2013.01); C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 6/007 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0242 (2013.01); C21D 8/0263 (2013.01); C21D 8/0273 (2013.01); C21D 8/0278 (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 38/10 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/18 (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 38/30 (2013.01); C22C 38/32 (2013.01); C22C 38/34 (2013.01); C22C 38/38 (2013.01); C22C 38/40 (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 38/52 (2013.01); C22C 38/54 (2013.01); C22C 38/58 (2013.01); C22C 38/60 (2013.01); C23C 2/02 (2013.01); C23C 2/06 (2013.01); C23C 2/285 (2013.01); C23C 2/29 (2022.08); C23C 2/40 (2013.01); C23C 28/021 (2013.01); C23C 28/025 (2013.01); C23C 28/3225 (2013.01); C23C 30/00 (2013.01); C23C 30/005 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01); Y10T 428/12458 (2015.01); Y10T 428/12792 (2015.01); Y10T 428/12958 (2015.01); Y10T 428/12965 (2015.01); Y10T 428/12972 (2015.01); Y10T 428/24942 (2015.01); Y10T 428/2495 (2015.01); Y10T 428/24967 (2015.01); Y10T 428/24983 (2015.01); Y10T 428/26 (2015.01); Y10T 428/263 (2015.01); Y10T 428/264 (2015.01); Y10T 428/265 (2015.01);
Abstract

A steel sheet having a tensile strength (TS) of 1180 MPa or more, high LME resistance, and good weld fatigue properties. The steel sheet has a specific chemical composition and a specific steel microstructure. Crystal grains containing an oxide of Si and/or Mn in a region within 4.9 μm in a thickness direction from a surface of the steel sheet have an average grain size in the range of 3 to 10 μm, the lowest Si concentration Land the lowest Mn concentration Lin the region within 4.9 μm in the thickness direction from the surface of the steel sheet and a Si concentration Tand a Mn concentration Tat a quarter thickness position of the steel sheet satisfy a specified formula.


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