发明名称 |
STEEL MATERIAL |
摘要 |
A steel material having a chemical composition of, by mass %, C: greater than 0.05% to 0.2%, Mn: 1% to 3%, Si: greater than 0.5% to 1.8%, Al: 0.01% to 0.5%, N: 0.001% to 0.015%, Ti or a sum of V and Ti: greater than 0.1% to 0.25%, Ti: 0.001% or more, Cr: 0% to 0.25%, Mo: 0% to 0.35%, and a balance: Fe and impurities, includes a steel structure being a multi-phase structure having a main phase made of ferrite of 50 area % or more, and a second phase containing one or two or more selected from a group consisting of bainite, martensite and austenite, in which an average nanohardness of the above-described second phase is less than 6.0 GPa, and when a boundary where a misorientation of crystals becomes 2° or more is defined as a grain boundary, and a region surrounded with the grain boundary is defined as a crystal grain, an average grain diameter of all crystal grains in the above-described main phase and the above-described second phase is 3 μm or less, and a proportion of a length of small-angle grain boundaries where the misorientation is 2° to less than 15° in a length of all grain boundaries is 15% or more. |
申请公布号 |
US2015071812(A1) |
申请公布日期 |
2015.03.12 |
申请号 |
US201314391417 |
申请日期 |
2013.07.22 |
申请人 |
NIPPON STEEL & SUMITOMO METAL CORPORATION |
发明人 |
Kawano Kaori;Tasaka Masahito;Nakazawa Yoshiaki;Tanaka Yasuaki;Tomida Toshiro |
分类号 |
C22C38/38;C22C38/28;C22C38/24;C22C38/00;C22C38/14;C22C38/06;C22C38/04;C22C38/02;C22C38/34;C22C38/22 |
主分类号 |
C22C38/38 |
代理机构 |
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代理人 |
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主权项 |
1. A steel material having a chemical composition of, by mass %,
C: greater than 0.05% to 0.2%, Mn: 1% to 3%, Si: greater than 0.5% to 1.8%, Al: 0.01% to 0.5%, N: 0.001% to 0.015%, Ti or a sum of V and Ti: greater than 0.1% to 0.25%, Ti: 0.001% or more, Cr: 0% to 0.25%, Mo: 0% to 0.35%, and a balance: Fe and impurities, the steel material comprising a steel structure being a multi-phase structure having a main phase made of ferrite of 50 area % or more, and a second phase containing one or two or more selected from a group consisting of bainite, martensite and austenite, wherein: an average nanohardness of the second phase is less than 6.0 GPa; and when a boundary where a misorientation of crystals becomes 2° or more is defined as a grain boundary, and a region surrounded with the grain boundary is defined as a crystal grain, an average grain diameter of all crystal grains in the main phase and the second phase is 3 μm or less, and a proportion of a length of small-angle grain boundaries where the misorientation is 2° to less than 15° in a length of all grain boundaries is 15% or more. |
地址 |
Tokyo JP |