发明授权
- 专利标题: High-strength hot-rolled steel sheet superior in stretch flange formability and method for production thereof
- 专利标题(中): 拉伸凸缘成型性优异的高强度热轧钢板及其制造方法
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申请号: US09909908申请日: 2001-07-23
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公开(公告)号: US06554918B2公开(公告)日: 2003-04-29
- 发明人: Takahiro Kashima , Shunichi Hashimoto
- 申请人: Takahiro Kashima , Shunichi Hashimoto
- 优先权: JP2000-221580 20000724
- 主分类号: C22C3800
- IPC分类号: C22C3800
摘要:
A high-strength hot-rolled steel sheet superior in stretch flange formability which comprises C (0.01-0.10 mass %), Si (no more than 1.0 mass %), Mn (no more than 2.5 mass %), P (no more than 0.08 mass %), S (no more than 0.005 mass %), Al (0.015-0.050 mass %), and Ti (0.10-0.30 mass %), with the remainder being substantially Fe, said hot-rolled steel sheet having a structure composed mainly of ferrite in which the unit grain is surrounded by grains such that adjacent grains differ in orientation more than 15°, the unit grain having an average particle diameter (d) no larger than 5 &mgr;m. This steel sheet is produced by the steps of heating, rolling, cooling, and coiling under the following conditions. Heating temperature: 1150-1300° C.; reduction in rolling at 900-840° C.: no less than 70%; cooling rate: no less than 60° C./s; and coiling temperature: 300-500° C. or 600-750° C.
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