Invention Grant
- Patent Title: High-strength hot-rolled steel sheet and method for manufacturing same
- Patent Title (中): 高强度热轧钢板及其制造方法
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Application No.: US12866513Application Date: 2009-02-04
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Publication No.: US08696832B2Publication Date: 2014-04-15
- Inventor: Shinjiro Kaneko , Kaneharu Okuda , Tetsuo Shimizu , Noriaki Moriyasu , Masahide Watabe
- Applicant: Shinjiro Kaneko , Kaneharu Okuda , Tetsuo Shimizu , Noriaki Moriyasu , Masahide Watabe
- Applicant Address: JP
- Assignee: JFE Steel Corporation
- Current Assignee: JFE Steel Corporation
- Current Assignee Address: JP
- Agency: DLA Piper LLP (US)
- Priority: JP2008-028453 20080208
- International Application: PCT/JP2009/052245 WO 20090204
- International Announcement: WO2009/099238 WO 20090813
- Main IPC: C22C38/14
- IPC: C22C38/14 ; C22C38/04 ; C21D8/02

Abstract:
A high-strength hot-rolled steel sheet has a tensile strength (TS) of 540 to 780 MPa, only small variations in strength, and excellent uniformity in strength using a general-purpose Ti-containing steel sheet, which is inexpensive. The high-strength hot-rolled steel sheet includes, on a mass percent basis, 0.05%-0.12% C, 0.5% or less Si, 0.8%-1.8% Mn, 0.030% or less P, 0.01% or less S, 0.005%-0.1% Al, 0.01% or less N, 0.030%-0.080% Ti, and the balance being Fe and incidental impurities. The microstructure have a bainitic ferrite fraction of 70% or more, and the amount of Ti present in a precipitate having a size of less than 20 nm is 50% or more of the value of Ti* calculated using formula (1): Ti*=[Ti]−48/14×[N] (1) where [Ti] and [N] represent a Ti content (percent by mass) and a N content (percent by mass), respectively, of the steel sheet.
Public/Granted literature
- US20100314010A1 HIGH-STRENGTH HOT-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING SAME Public/Granted day:2010-12-16
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