发明名称 |
HOT-ROLLED STEEL SHEET AND METHOD FOR PRODUCING SAME |
摘要 |
There are provided a high-strength hot-rolled steel sheet securing low-temperature toughness and having excellent stretch flangeability by controlling a structural fraction and a hardness difference among structures, and a manufacturing method thereof. A hot-rolled steel sheet contains: C: 0.01 to 0.2%; Si: 0.001 to 2.5% or less; Mn: 0.10 to 4.0% or less; P: 0.10% or less; S: less than 0.03%; Al: 0.001 to 2.0%; N: less than 0.01%; Ti: (0.005 + 48/14[N] + 48/32[S])% or more and 0.3% or less; Nb: 0 to 0.06%; Cu: 0 to 1.2%; Ni: 0 to 0.6%; Mo: 0 to 1%; V: 0 to 0.2%; Cr: 0 to 2%; Mg: 0 to 0.01 %; Ca: 0 to 0.01%; REM: 0 to 0.1 %; and B: 0 to 0.002%, and has: an texture in which, at a central portion of a sheet thickness located between 3/8 to 5/8 thickness positions of the sheet thickness from a surface of the steel sheet, an average value of X-ray random intensity ratios of a group of {100}<011> to {223}<110> orientations of a sheet plane is 6.5 or less and an X-ray random intensity ratio of a {332}<113> crystal orientation is 5.0 or less; and a microstructure in which a total area ratio of tempered martensite, martensite and lower bainite is more than 85 %, and an average crystal grain diameter is 12.0 µm or less. |
申请公布号 |
EP2801637(A1) |
申请公布日期 |
2014.11.12 |
申请号 |
EP20120864393 |
申请日期 |
2012.12.27 |
申请人 |
NIPPON STEEL & SUMITOMO METAL CORPORATION |
发明人 |
SHUTO, HIROSHI;YOKOI, TATSUO;KANZAWA, YUUKI;FUJITA, NOBUHIRO;NIIYA, RYOHTA;SAITOH, SHINYA |
分类号 |
C22C38/06;B32B15/01;C21D1/25;C21D8/02;C21D9/46;C22C38/00;C22C38/02;C22C38/04;C22C38/08;C22C38/12;C22C38/14;C22C38/20;C22C38/26;C22C38/28;C22C38/58;C23C2/02;C25D5/36 |
主分类号 |
C22C38/06 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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