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:
Mar. 30, 2010
Filed:
Sep. 17, 2004
Hiromi Yoshida, Hiroshima, JP;
Kaneharu Okuda, Chiba, JP;
Toshiaki Urabe, Chiba, JP;
Yoshihiro Hosoya, Chiba, JP;
Hiromi Yoshida, Hiroshima, JP;
Kaneharu Okuda, Chiba, JP;
Toshiaki Urabe, Chiba, JP;
Yoshihiro Hosoya, Chiba, JP;
JFE Steel Corporation, , JP;
Abstract
A high-strength steel sheet is useful for applications to automobile steel sheets and the like and has excellent deep drawability, a tensile strength (TS) of as high as 440 MPa or more, and a high r value (average r value ≧1.2), and a process for producing the steel sheet. The steel sheet has a composition containing, by % by mass, 0.010 to 0.050% of C, 1.0% or less of Si, 1.0 to 3.0% of Mn, 0.005 to 0.1% of P, 0.01% or less of S, 0.005 to 0.5% of Al, 0.01% or less of N, and 0.01 to 0.3% of Nb, the Nb and C contents in steel satisfying the relation, (Nb/93)/(C/12)=0.2 to 0.7, and the balance substantially including Fe and inevitable impurities. The steel microstructure contains a ferrite phase and a martensite phase at area ratios of 50% or more and 1% or more, respectively, and the average r value is 1.2 or more.