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:
Jul. 22, 2025

Filed:

Dec. 10, 2019
Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Kazuki Endoh, Tokyo, JP;

Yoshiyasu Kawasaki, Tokyo, JP;

Yuki Toji, Tokyo, JP;

Yoshimasa Funakawa, Tokyo, JP;

Mai Aoyama, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C21D 9/46 (2006.01); B21C 47/02 (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); C23C 2/02 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); B21C 47/02 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (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); C23C 2/02 (2013.01); C23C 2/0224 (2022.08); C23C 2/024 (2022.08); C23C 2/28 (2013.01); C23C 2/40 (2013.01); C21D 2211/001 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

A high strength steel sheet and method for manufacturing the same. The steel sheet has a specified chemical composition and a specified microstructure. A value calculated by dividing the average Mn content in retained austenite by the average Mn content in ferrite is 1.5 or more, a value calculated by dividing the sum of the area fraction of as-quenched martensite having a circle-equivalent grain size of 3 μm or more and the area fraction of retained austenite having a circle-equivalent grain size of 3 μm or more by the sum of the area fraction of all the as-quenched martensite and the area fraction of all the retained austenite is less than 0.4, and a value calculated by dividing the area fraction of retained austenite grains adjacent to three or more ferrite grains having different crystal orientations by the area fraction of all the retained austenite is less than 0.6.


Find Patent Forward Citations

Loading…