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. 10, 2022
Filed:
Mar. 31, 2017
Nippon Steel Corporation, Tokyo, JP;
Takafumi Yokoyama, Tokyo, JP;
Riki Okamoto, Tokyo, JP;
Yuji Yamaguchi, Tokyo, JP;
Kazuki Shiokawa, Tokyo, JP;
Yuichi Nakahira, Tokyo, JP;
Hiroyuki Kawata, Tokyo, JP;
NIPPON STEEL CORPORATION, Tokyo, JP;
Abstract
A cold-rolled steel sheet is provided that has a tensile strength of 980 MPa or more, and has a prescribed chemical composition. The microstructure is composed of, in area %, ferrite: 1 to 29%, retained austenite: 5 to 20%, martensite: less than 10%, pearlite: less than 5%, and the balance: bainite and/or tempered martensite. The total sum of the lengths of phase boundaries where ferrite comes in contact with martensite or retained austenite having a circle-equivalent radius of 1 μm or more is 100 μm or less per 1000 μm. The cold-rolled steel sheet is excellent in workability and low-temperature toughness, and in particular is excellent in low-temperature toughness after introduction of plastic strain.