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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 11408044 B1

PDFFull Text
Date of Patent:
Aug. 09, 2022

Filed:

Feb. 09, 2018

High-strength steel sheet and method for producing the same

Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Hidekazu Minami, Tokyo, JP;

Fusae Shiimori, Tokyo, JP;

Shinjiro Kaneko, Tokyo, JP;

Takashi Kobayashi, Tokyo, JP;

Yuji Tanaka, Tokyo, JP;

Assignee:

JFE STEEL CORPORATION, Tokyo, JP;

Attorney:

Oliff PLC

Primary Examiner:

Anthony M Liang

Int. Cl.
CPC ...
C21D 9/46 (2006.01); C21D 8/02 (2006.01); C21D 6/00 (2006.01); C21D 1/26 (2006.01); C22C 38/24 (2006.01); C22C 38/60 (2006.01); C22C 38/16 (2006.01); C22C 38/14 (2006.01); C22C 38/12 (2006.01); C22C 38/10 (2006.01); C22C 38/08 (2006.01); C22C 38/06 (2006.01); C22C 38/04 (2006.01); C22C 38/02 (2006.01); C22C 38/00 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); C21D 1/26 (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 8/0263 (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 38/24 (2013.01); C22C 38/60 (2013.01); C21D 2211/001 (2013.01); C21D 2211/008 (2013.01);
Abstract

There is provided a high-strength steel sheet and a method for producing the same. The high-strength steel sheet has a specified chemical composition and a steel microstructure including, by area fraction, 75.0% or more tempered martensite, 1.0% or more and 20.0% or less fresh martensite, and 5.0% or more and 20.0% or less retained austenite. A hardness ratio of the fresh martensite to the tempered martensite is 1.5 or more and 3.0 or less, the ratio of the maximum KAM value in the tempered martensite in the vicinity of the heterophase interface between the tempered martensite and the fresh martensite to the average KAM value in the tempered martensite is 1.5 or more and 30.0 or less, and the average of ratios of grain sizes of prior austenite grains in the rolling direction to those in the thickness direction is 2.0 or less.

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