Invention Grant
- Patent Title: High-strength cold-rolled steel sheet having excellent uniform elongation and hole expandability
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Application No.: US15249595Application Date: 2016-08-29
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Publication No.: US10066283B2Publication Date: 2018-09-04
- Inventor: Yuri Toda , Riki Okamoto , Nobuhiro Fujita , Kohichi Sano , Hiroshi Yoshida , Toshio Ogawa
- Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
- Applicant Address: JP Tokyo
- Assignee: NIPPON STEEL AND SUMITOMO METAL CORPORATION
- Current Assignee: NIPPON STEEL AND SUMITOMO METAL CORPORATION
- Current Assignee Address: JP Tokyo
- Agency: Birch, Stewart, Kolasch & Birch, LLP
- Priority: JP2011-095254 20110421
- Main IPC: C22C38/02
- IPC: C22C38/02 ; C22C38/04 ; C22C38/06 ; C23C2/06 ; C23C2/02 ; C23C2/28 ; C22C38/00 ; C22C38/12 ; C22C38/14 ; C21D8/02 ; C22C38/08 ; C22C38/16 ; C22C38/22 ; C22C38/28 ; C22C38/32 ; C22C38/38 ; C21D9/46 ; C23C2/40

Abstract:
This high-strength cold-rolled steel sheet having excellent uniform elongation and hole expandability contains, C: 0.01 to 0.4%; Si: 0.001 to 2.5%; Mn: 0.001 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 at a sheet thickness center portion, an average value of pole densities of the {100} to {223} orientation group is 5.0 or less, and a pole density of the {332} crystal orientation is 4.0 or less, a metal structure contains 5 to 80% of ferrite, 5 to 80% of bainite, and 1% or less of martensite in terms of an area ratio and the total of martensite, pearlite, and retained austenite is 5% or less, and an r value (rC) in a direction perpendicular to a rolling direction is 0.70 or more and an r value (r30) in a direction 30° from the rolling direction is 1.10 or less.
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