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.:
Date of Patent:
Dec. 20, 2016
Filed:
Jun. 27, 2012
Jun Haga, Nishinomiya, JP;
Takuya Nishio, Nishinomiya, JP;
Masayuki Wakita, Nishinomiya, JP;
Yasuaki Tanaka, Nishinomiya, JP;
Norio Imai, Nishinomiya, JP;
Toshiro Tomida, Kobe, JP;
Jun Haga, Nishinomiya, JP;
Takuya Nishio, Nishinomiya, JP;
Masayuki Wakita, Nishinomiya, JP;
Yasuaki Tanaka, Nishinomiya, JP;
Norio Imai, Nishinomiya, JP;
Toshiro Tomida, Kobe, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
Abstract
A high-strength cold-rolled steel sheet excellent in ductility, work hardenability, and stretch flangeability, and having tensile strength of 780 MPa or more includes: a chemical composition containing, in mass percent, C: more than 0.020% to less than 0.30%, Si: more than 0.10% to 3.00% or less, Mn: more than 1.00% to 3.50% or less; and metallurgical structure whose main phase is a low-temperature transformation product, and whose secondary phase contains retained austenite. The retained austenite has a volume fraction relative to overall structure of more than 4.0% to less than 25.0% and an average grain size of less than 0.80 μm, and of the retained austenite, the number density of retained austenite grains whose grain size is 1.2 μm or more is 3.0×10grains/μmor less.