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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.

Patent No.:

US 12258646 B1

PDFFull Text
Date of Patent:
Mar. 25, 2025

Filed:

Feb. 21, 2020

High-strength steel sheet and method for producing same

Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Hidekazu Minami, Tokyo, JP;

Yuji Tanaka, Tokyo, JP;

Takeshi Yokota, Tokyo, JP;

Assignee:

JFE STEEL CORPORATION, Tokyo, JP;

Attorney:

KENJA IP LAW PC

Primary Examiner:

Jophy S Koshy

Int. Cl.
CPC ...
C21D 9/46 (2006.01); B32B 15/01 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (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 38/38 (2006.01); C22C 38/40 (2006.01); C23C 2/02 (2006.01); C23C 2/28 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); B32B 15/013 (2013.01); C21D 6/004 (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); 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 38/06 (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 38/38 (2013.01); C22C 38/40 (2013.01); C23C 2/02 (2013.01); C23C 2/0224 (2022.08); C23C 2/024 (2022.08); C23C 2/28 (2013.01); C21D 2211/001 (2013.01); C21D 2211/005 (2013.01);
Abstract

A high-strength steel sheet comprises: a chemical composition containing C, Si, Mn, P, S, Al, N, Mo, Cr, Ca, and Sb with a balance consisting of Fe and inevitable impurities, wherein [% Si], [% Mn], [% P], [% Mo], and [% Cr] satisfy a predetermined relationship; a steel microstructure that contains ferrite, hard phase, and retained austenite and in which a carbon concentration in the retained austenite is 0.55% or more and 1.10% or less, an amount of diffusible hydrogen in the steel sheet is 0.80 mass ppm or less, a surface layer softening thickness is 5 μm or more and 150 μm or less, and a corresponding grain boundary frequency in a surface layer of the steel sheet after a high-temperature tensile test is 0.45 or less; and a tensile strength of 980 MPa or more.

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