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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 11091817 B1

PDFFull Text
Date of Patent:
Aug. 17, 2021

Filed:

Aug. 29, 2017

High-strength steel sheet and method for manufacturing the same

Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Lingling Yang, Tokyo, JP;

Noriaki Kohsaka, Tokyo, JP;

Tatsuya Nakagaito, Tokyo, JP;

Yoshimasa Funakawa, Tokyo, JP;

Assignee:

JFE Steel Corporation, Tokyo, JP;

Attorney:

RatnerPrestia

Primary Examiner:

Anthony J Zimmer

Assistant Examiner:

Dean Mazzola

Int. Cl.
CPC ...
C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 38/14 (2006.01); C22C 38/60 (2006.01); C21D 9/56 (2006.01); C22C 38/00 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/10 (2006.01); C22C 38/12 (2006.01); C22C 38/16 (2006.01); C22C 38/22 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/34 (2006.01); C22C 38/38 (2006.01); C23C 2/02 (2006.01); C23C 2/06 (2006.01); C23C 2/40 (2006.01);
U.S. Cl.
CPC ...
C21D 8/0263 (2013.01); C21D 9/46 (2013.01); C21D 9/563 (2013.01); C22C 38/00 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/008 (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 38/22 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/34 (2013.01); C22C 38/38 (2013.01); C22C 38/60 (2013.01); C23C 2/02 (2013.01); C23C 2/06 (2013.01); C23C 2/40 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

Provided are a high-strength steel sheet having high strength of a yield strength of 550 MPa or more and a method for manufacturing the same. The high-strength steel sheet has a specified chemical composition and a microstructure, where observed in a cross section in a thickness direction perpendicular to a rolling direction, including a martensite phase having a volume fraction of 50% to 80%, and a ferrite phase having an average grain diameter of 13 μm or less, wherein a volume fraction of ferrite grains having an aspect ratio of 2.0 or less with respect to the whole ferrite phase is 70% or more, and wherein an average length in a longitudinal direction (in a width direction of the steel sheet) of the ferrite grains is 20 μm or less, and a yield strength (YP) of 550 MPa or more.

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