Invention Grant
- Patent Title: High-strength steel sheet and method for producing the same
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Application No.: US16076381Application Date: 2017-02-07
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Publication No.: US11111553B2Publication Date: 2021-09-07
- Inventor: Yusuke Kimata , Yoshihiko Ono , Kenji Kawamura
- Applicant: JFE STEEL CORPORATION
- Applicant Address: JP Tokyo
- Assignee: JFE STEEL CORPORATION
- Current Assignee: JFE STEEL CORPORATION
- Current Assignee Address: JP Tokyo
- Agency: Oliff PLC
- Priority: JPJP2016-023374 20160210,JPJP2016-235853 20161205
- International Application: PCT/JP2017/004311 WO 20170207
- International Announcement: WO2017/138504 WO 20170817
- Main IPC: C21D8/02
- IPC: C21D8/02 ; C21D9/46 ; C22C38/06 ; C22C38/00 ; C22C38/02 ; C22C38/04 ; C22C38/42 ; C22C38/44 ; C22C38/46 ; C22C38/48 ; C22C38/50 ; C22C38/58 ; C21D6/00 ; C22C38/54

Abstract:
A high-strength steel sheet having a tensile strength (TS) of 1,320 MPa or more and good workability. The high-strength steel sheet has a specific component composition and a steel microstructure containing, on an area-percentage basis with respect to the entire steel microstructure, 40% or more and less than 85% of a lower bainite, 5% or more and less than 40% martensite including tempered martensite, 10% or more and 30% or less retained austenite, and 10% or less (including 0%) polygonal ferrite, the retained austenite having an average C content of 0.60% by mass or more. Additionally, a Mn segregation value at a surface of the steel sheet is 0.8% or less, the ratio R/t of a limit bending radius (R) to a thickness (t) of the steel sheet is 2.0 or less, and tensile strength×total elongation of the steel sheet is 15,000 MPa % or more.
Public/Granted literature
- US20190040483A1 HIGH-STRENGTH STEEL SHEET AND METHOD FOR PRODUCING THE SAME Public/Granted day:2019-02-07
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