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:
Nov. 30, 2021
Filed:
Mar. 08, 2018
Jfe Steel Corporation, Tokyo, JP;
Takuya Hirashima, Tokyo, JP;
Kenji Kawamura, Tokyo, JP;
Yoshihiko Ono, Tokyo, JP;
Yuma Honda, Tokyo, JP;
JFE STEEL CORPORATION, Tokyo, JP;
Abstract
A high-strength cold rolled steel sheet having mechanical characteristics having a tensile strength of not less than 780 MPa, a yield ratio of not more than 70%, and a small in-plane anisotropy of a tensile characteristicis obtained by hot rolling a steel slab comprising by mass % C: 0.07 to 0.12%, Si: not more than 0.7%, Mn: 2.2 to 2.8% and Ti and Nb: 0.02 to 0.08% in total, and cold rolling the sheet, followed by continuous annealing to form a steel texture comprised of ferrite having an area ratio of 40 to 80% with respect to the whole texture, and a second phase constituted by tempered martensite, fresh martensite and bainite, wherein the total area ratio of the bainite and the tempered martensite to the second phase is 50 to 80%, and the aspect ratio of the fresh martensite is in the range of 1.0 to 1.5.