Invention Grant
- Patent Title: High-strength hot-rolled steel sheet and method for manufacturing the same
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Application No.: US15747583Application Date: 2016-07-20
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Publication No.: US11578375B2Publication Date: 2023-02-14
- Inventor: Kazuhiko Yamazaki , Shunsuke Toyoda , Noriaki Moriyasu , Kentaro Irisa
- 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: JPJP2015-147454 20150727,JP2016-027728 20160217
- International Application: PCT/JP2016/003396 WO 20160720
- International Announcement: WO2017/017933 WO 20170202
- Main IPC: C21D8/02
- IPC: C21D8/02 ; C21D9/46 ; C22C38/38 ; C22C38/00 ; C22C38/06 ; C22C38/28 ; C22C38/32 ; C22C38/60 ; C22C38/20 ; C22C38/22 ; C22C38/24 ; C22C38/26 ; C22C38/02 ; C22C38/40 ; C22C38/04 ; C22C38/34

Abstract:
A high-strength hot-rolled steel sheet that has excellent punching workability and hole expandability, and a method for manufacturing the same. The hot-rolled steel sheet has a tensile strength of 980 MPa or more. The hot-rolled steel sheet has a chemical composition containing C, Si, Mn, P, S, Al, N, Ti, Cr, and B, and has a microstructure including a bainite phase having an area ratio of 85% or more as a main phase, and a martensite phase or martensite-austenite constituent having an area ratio of 15% or less as a second phase, the balance being a ferrite phase. The second phase has an average grain diameter of 3.0 μm or less, prior-austenite grains have an average aspect ratio of 1.3 or more and 5.0 or less, and recrystallized prior-austenite grains have an area ratio of 15% or less relative to non-recrystallized prior-austenite grains.
Public/Granted literature
- US20180237874A1 HIGH-STRENGTH HOT-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME Public/Granted day:2018-08-23
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