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.

Date of Patent:
Feb. 10, 2015

Filed:

Jan. 26, 2011
Applicants:

Kohichi Sano, Tokyo, JP;

Chisato Wakabayashi, Tokyo, JP;

Hiroyuki Kawata, Tokyo, JP;

Riki Okamoto, Tokyo, JP;

Naoki Yoshinaga, Tokyo, JP;

Kaoru Kawasaki, Tokyo, JP;

Natsuko Sugiura, Tokyo, JP;

Nobuhiro Fujita, Tokyo, JP;

Inventors:

Kohichi Sano, Tokyo, JP;

Chisato Wakabayashi, Tokyo, JP;

Hiroyuki Kawata, Tokyo, JP;

Riki Okamoto, Tokyo, JP;

Naoki Yoshinaga, Tokyo, JP;

Kaoru Kawasaki, Tokyo, JP;

Natsuko Sugiura, Tokyo, JP;

Nobuhiro Fujita, Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/18 (2006.01); C21D 8/02 (2006.01); C21D 8/04 (2006.01); C23C 2/04 (2006.01); C23C 2/26 (2006.01); C23C 2/28 (2006.01); C21D 9/48 (2006.01);
U.S. Cl.
CPC ...
C22C 38/02 (2013.01); C21D 8/0436 (2013.01); C21D 8/0473 (2013.01); C22C 38/04 (2013.01); C23C 2/04 (2013.01); C23C 2/26 (2013.01); C23C 2/28 (2013.01); C21D 9/48 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/008 (2013.01); C22C 38/06 (2013.01);
Abstract

A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 μm to 1 μm, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.


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