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:
Aug. 29, 2017

Filed:

Jun. 05, 2012
Applicants:

Sae Mizuta, Kakogawa, JP;

Yuichi Futamura, Kakogawa, JP;

Yukihiro Utsumi, Kakogawa, JP;

Inventors:

Sae Mizuta, Kakogawa, JP;

Yuichi Futamura, Kakogawa, JP;

Yukihiro Utsumi, Kakogawa, JP;

Assignee:

Kobe Steel, Ltd., Kobe-shi, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 38/04 (2006.01); C22C 38/02 (2006.01); C21D 1/20 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/18 (2006.01); C21D 8/04 (2006.01);
U.S. Cl.
CPC ...
C21D 1/20 (2013.01); C21D 8/0447 (2013.01); C21D 8/0463 (2013.01); C21D 8/0473 (2013.01); C21D 9/46 (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 38/18 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

The invention relates to a steel sheet having a tensile strength of 1180 MPa or more, which excels in workability and cold brittleness resistance. The high-strength steel sheet contains 0.10% to 0.30% of C, 1.40% to 3.0% of Si, 0.5% to 3.0% of Mn, 0.1% or less of P, 0.05% or less of S, 0.005% to 0.20% of Al, 0.01% or less of N, 0.01% or less of O, as well as Fe and inevitable impurities. The steel sheet has: (i) a ferrite volume fraction of 5% to 35% and a bainitic ferrite and/or tempered martensite volume fraction of 60% or more; (ii) a MA constituent volume fraction of 6% or less (excluding 0%); and (iii) a retained austenite volume fraction of 5% or more.


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