Invention Grant
- Patent Title: High-strength steel sheet and method for manufacturing the same
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Application No.: US15542203Application Date: 2015-08-28
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Publication No.: US10760142B2Publication Date: 2020-09-01
- Inventor: Nobusuke Kariya , Yoshihiko Ono , Yoshimasa Funakawa , Kazuma Mori , Reiko Sugihara , 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: RatnerPrestia
- Priority: com.zzzhc.datahub.patent.etl.us.BibliographicData$PriorityClaim@7102f40b
- International Application: PCT/JP2015/004380 WO 20150828
- International Announcement: WO2016/113780 WO 20160721
- Main IPC: C21D9/46
- IPC: C21D9/46 ; C22C38/14 ; C22C38/60 ; C22C38/00 ; C21D6/00 ; C21D8/02 ; C22C38/02 ; C22C38/04 ; C22C38/06 ; C22C38/08 ; C22C38/12 ; C22C38/16 ; C22C38/22 ; C22C38/24 ; C22C38/26 ; C22C38/28 ; C22C38/32 ; C22C38/38

Abstract:
Provided are a high-strength steel sheet and a method for manufacturing the steel sheet. The high-strength steel sheet has a specified chemical composition with the balance being Fe and inevitable impurities, a microstructure including, in terms of area ratio, 30% or more of a ferrite phase, 40% to 65% of a bainite phase and/or a martensite phase, and 5% or less of cementite, in which, in a surface layer that is a region within 50 μm from the surface in the thickness direction, the area ratio of a ferrite phase is 40% to 55% and the total area ratio of a bainite phase having a grain diameter of more than 5 μm and/or a martensite phase having a grain diameter of more than 5 μm is 20% or less, and a tensile strength is 980 MPa or more.
Public/Granted literature
- US20180002777A1 HIGH-STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME Public/Granted day:2018-01-04
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