发明申请
- 专利标题: HOT-ROLLED STEEL SHEET EXCELLENT IN FATIGUE PROPERTIES AND STRETCH-FLANGE FORMABILITY AND METHOD FOR MANUFACTURING THE SAME
- 专利标题(中): 热轧性能优异的热轧钢板和拉伸法兰形成性及其制造方法
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申请号: US12934039申请日: 2008-11-12
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公开(公告)号: US20110017360A1公开(公告)日: 2011-01-27
- 发明人: Naoki Yoshinaga , Masafumi Azuma , Yasuharu Sakuma , Naoki Maruyama
- 申请人: Naoki Yoshinaga , Masafumi Azuma , Yasuharu Sakuma , Naoki Maruyama
- 优先权: JP2008-079591 20080326
- 国际申请: PCT/JP2008/070612 WO 20081112
- 主分类号: C21D8/02
- IPC分类号: C21D8/02 ; C22C38/00 ; B32B15/01 ; C22C38/02 ; C22C38/04
摘要:
This hot-rolled steel sheet contains, in terms of mass%, C: 0.015% or more to less than 0.040%; Si: less than 0.05%; Mn: 0.9% or more to 1.8% or less; P: less than 0.02%; S: less than 0.01%; Al: less than 0.1%; N: less than 0.006%; and Ti: 0.05% or more to less than 0.11%, with the remainder being Fe and inevitable impurities, wherein Ti/C is in a range of 2.5 or more to less than 3.5, Nb, Zr, V, Cr, Mo, B and W are not included, a microstructure includes a mixed microstructure of polygonal ferrite and quasi-polygonal ferrite in a proportion of greater than 96%, a maximum tensile strength is 520 MPa or more and less than 720 MPa, an aging index AI is more than 15 MPa, a product of a hole expansion ratio (A) % and a total elongation (El) % is 2350 or more, and a fatigue limit is 200 MPa or more.
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