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:
May. 17, 2022
Filed:
Jan. 21, 2019
Jfe Steel Corporation, Tokyo, JP;
Seigo Tsuchihashi, Tokyo, JP;
Shinsuke Komine, Tokyo, JP;
Tatsuya Nakagaito, Tokyo, JP;
Hidekazu Minami, Tokyo, JP;
JFE STEEL CORPORATION, Tokyo, JP;
Abstract
A high-strength cold-rolled steel sheet or high-strength coated steel sheet that has a tensile strength (TS) of 780 MPa or more and has high ductility, stretch-flangeability, and in-plane stability of stretch-flangeability and methods for producing the same. The high-strength cold-rolled steel sheet has a specified chemical composition and a microstructure comprising, by area fraction, in a range of 50% to 80% of ferrite, 8% or less of martensite with an average grain size of 2.5 μm or less, in a range of 6% to 15% of retained austenite, and in a range of 3% to 40% of tempered martensite. A ratio f/fbeing 50% or less, where fdenotes the area fraction of martensite and fdenotes the total area fraction of martensite and tempered martensite, and a standard deviation of the grain size of martensite at certain portions being 0.7 μm or less.