发明申请
- 专利标题: HIGH-STRENGTH HOT-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING SAME
- 专利标题(中): 高强度热轧钢板及其制造方法
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申请号: US12866382申请日: 2009-02-04
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公开(公告)号: US20100319819A1公开(公告)日: 2010-12-23
- 发明人: Shinjiro Kaneko , Kaneharu Okuda , Tetsuo Shimizu , Noriaki Moriyasu , Masahide Watabe
- 申请人: Shinjiro Kaneko , Kaneharu Okuda , Tetsuo Shimizu , Noriaki Moriyasu , Masahide Watabe
- 优先权: JP2008-028455 20080208
- 国际申请: PCT/JP2009/052244 WO 20090204
- 主分类号: C21D8/02
- IPC分类号: C21D8/02 ; C22C38/02 ; C22C38/04 ; C22C38/06 ; C22C38/14
摘要:
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 volume fraction of polygonal ferrite 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.
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