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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 11345973 B1

PDFFull Text
Date of Patent:
May. 31, 2022

Filed:

Mar. 29, 2018

High-strength steel sheet and method for manufacturing the same

Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Lingling Yang, Tokyo, JP;

Tatsuya Nakagaito, Tokyo, JP;

Gosuke Ikeda, Tokyo, JP;

Assignee:

JFE STEEL CORPORATION, Tokyo, JP;

Attorney:

RatnerPrestia

Primary Examiner:

Jenny R Wu

Int. Cl.
CPC ...
C21D 9/46 (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 38/10 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/38 (2006.01); C22C 38/60 (2006.01); C23C 2/02 (2006.01); C23C 2/12 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (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); C21D 8/0247 (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 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/38 (2013.01); C22C 38/60 (2013.01); C23C 2/02 (2013.01); C23C 2/12 (2013.01); C23C 2/28 (2013.01); C23C 2/40 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

Provided are a high-strength steel sheet having a yield strength of 550 MPa or more and excellent fatigue-strength of a weld and a method for manufacturing the steel sheet. A high-strength steel sheet has a specified chemical composition, a steel microstructure observed in a cross section in a thickness direction parallel to a rolling direction including 40% to 75% of a martensite phase in terms of volume fraction, in which a total volume fraction of martensite grains whose average grain diameter ratios with respect to adjacent ferrite grains are ¼ or more and 1 or less is 60% or more with respect to an entire martensite phase, and a yield strength (YP) of 550 MPa or more.

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