Invention Grant
- Patent Title: Manufacturing method of a high-strength cold-rolled steel sheet having excellent local deformability
- Patent Title (中): 具有优异的局部变形性的高强度冷轧钢板的制造方法
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Application No.: US14110891Application Date: 2012-04-12
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Publication No.: US09347122B2Publication Date: 2016-05-24
- Inventor: Yoshihiro Suwa , Kazuaki Nakano , Kunio Hayashi , Riki Okamoto , Nobuhiro Fujita , Kohichi Sano
- Applicant: Yoshihiro Suwa , Kazuaki Nakano , Kunio Hayashi , Riki Okamoto , Nobuhiro Fujita , Kohichi Sano
- Applicant Address: JP Tokyo
- Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
- Current Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
- Current Assignee Address: JP Tokyo
- Agency: Birch, Stewart, Kolasch & Birch, LLP
- Priority: JP2011-089250 20110413
- International Application: PCT/JP2012/060065 WO 20120412
- International Announcement: WO2012/141263 WO 20121018
- Main IPC: C21D8/02
- IPC: C21D8/02 ; C21D8/04 ; C22C38/22 ; C22C38/00 ; C22C38/02 ; C22C38/04 ; C22C38/06 ; C22C38/12 ; C22C38/14 ; B32B15/01 ; C22C38/08 ; C22C38/10 ; C22C38/16 ; C22C38/26 ; C22C38/28 ; C22C38/38 ; C21D9/46

Abstract:
This high-strength cold-rolled steel sheet contains, in mass %, C: 0.02% to 0.20%; Si: 0.001% to 2.5%; Mn: 0.01% to 4.0%; P: 0.001% to 0.15%; S: 0.0005% to 0.03%; Al: 0.001% to 2.0%; N: 0.0005% to 0.01%; and O: 0.0005% to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which an area ratio of bainite in a metal structure is 95% or more, at a sheet thickness center portion being a range of ⅝ to ⅜ in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100} to {223} orientation group is 4.0 or less, and a pole density of the {332} crystal orientation is 5.0 or less, and a mean volume diameter of crystal grains in the metal structure is 7 μm or less.
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