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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 10156005 B1

PDFFull Text
Date of Patent:
Dec. 18, 2018

Filed:

Jul. 18, 2014

High-yield-ratio, high-strength cold rolled steel sheet and production method therefor

Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Katsutoshi Takashima, Tokyo, JP;

Yoshihiko Ono, Tokyo, JP;

Kohei Hasegawa, Tokyo, JP;

Assignee:

JFE Steel Corporation, , JP;

Attorney:

DLA Piper LLP (US)

Primary Examiner:

Deborah Yee

Int. Cl.
CPC ...
C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/14 (2006.01); C22C 38/12 (2006.01); C21D 9/46 (2006.01); C21D 8/02 (2006.01); C22C 38/38 (2006.01); C22C 38/00 (2006.01); C22C 38/08 (2006.01); C22C 38/16 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C21D 1/84 (2006.01); C21D 6/00 (2006.01); C21D 8/04 (2006.01); C21D 1/25 (2006.01);
U.S. Cl.
CPC ...
C22C 38/38 (2013.01); C21D 1/25 (2013.01); C21D 1/84 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0221 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0263 (2013.01); C21D 8/0278 (2013.01); C21D 8/0463 (2013.01); C21D 8/0473 (2013.01); C22C 38/00 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C21D 9/46 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/008 (2013.01);
Abstract

A steel sheet includes a microstructure containing a volume fraction of 20% to 55% of ferrite having an average grain size of 7 μm or less, a volume fraction of 5% to 15% of retained austenite, a volume fraction of 0.5% to 7% of martensite having an average grain size of 4 μm or less, and a structure composed of bainite and/or tempered martensite and having an average grain size of 6 μm or less, and a difference in nano-hardness between ferrite and the structure composed of bainite and/or tempered martensite being 3.5 GPa or less and a difference in nano-hardness between the structure composed of bainite and/or tempered martensite and martensite being 2.5 GPa or less.

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