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:
Jul. 28, 2015
Filed:
Dec. 24, 2010
Yoichi Makimizu, Fukuyama, JP;
Yoshitsugu Suzuki, Fukuyama, JP;
Mai Miyata, Fukuyama, JP;
Naoto Yoshimi, Kawasaki, JP;
Junichiro Hirasawa, Chiba, JP;
Shinji Otsuka, Fukuyama, JP;
Hideki Nagano, Fukuyama, JP;
Kohei Hasegawa, Fukuyama, JP;
Yoichi Makimizu, Fukuyama, JP;
Yoshitsugu Suzuki, Fukuyama, JP;
Mai Miyata, Fukuyama, JP;
Naoto Yoshimi, Kawasaki, JP;
Junichiro Hirasawa, Chiba, JP;
Shinji Otsuka, Fukuyama, JP;
Hideki Nagano, Fukuyama, JP;
Kohei Hasegawa, Fukuyama, JP;
JFE Steel Corporation, Tokyo, JP;
Abstract
A high-strength cold-rolled steel sheet having high chemical convertibility and a tensile strength of 590 MPa or more and a method for producing such a steel sheet are provided. The steel sheet contains, in terms of percent by mass, C: 0.05 to 0.3%, Si: 0.6 to 3.0%, Mn: 1.0 to 3.0%, P: 0.1% or less, S: 0.05% or less, Al: 0.01 to 1%, N: 0.01% or less, and the balance being Fe and unavoidable impurities. The coverage ratio of reduced iron on a steel sheet surface is 40% or more. In order to produce such a steel sheet, an oxidation treatment is performed after cold rolling. Subsequently, annealing is conducted in a furnace in a 1 to 10 vol % H+balance Ngas atmosphere with a dew point of −25° C. or less.