发明名称 |
High strength hot-rolled steel sheet and method for manufacturing the same |
摘要 |
A high strength hot-rolled steel sheet with a tensile strength of not less than 590 MPa which exhibits excellent bake hardenability and stretch-flangeability has a chemical composition including, in terms of mass %, C at 0.040 to 0.10%, Si at not more than 0.3%, Mn at 1.7 to 2.5%, P at not more than 0.030%, S at not more than 0.005%, Al at not more than 0.1% and N at 0.006 to 0.025%, and microstructure wherein a bainite phase represents not less than 60%, the total of a ferrite phase and a pearlite phase represents not more than 10%, and the bainite phase includes grains among which cementite grains have been precipitated at not less than 1.4×104 grains/mm2 and the cementite grains have an average grain diameter of not more than 1.5 μm. |
申请公布号 |
US9284618(B2) |
申请公布日期 |
2016.03.15 |
申请号 |
US201113699119 |
申请日期 |
2011.05.23 |
申请人 |
JFE Steel Corporation |
发明人 |
Kohsaka Noriaki;Seto Kazuhiro;Kawabe Hidetaka;Tanaka Yasushi |
分类号 |
C21D8/02;C21D6/00;C21D9/46;C22C38/00;C22C38/02;C22C38/04;C22C38/06;C22C38/12;C22C38/14;C22C38/08;C22C38/22;C22C38/24;C22C38/38 |
主分类号 |
C21D8/02 |
代理机构 |
DLA Piper LLP (US) |
代理人 |
DLA Piper LLP (US) |
主权项 |
1. A high strength hot-rolled steel sheet with a tensile strength of not less than 590 MPa which has a chemical composition comprising, in terms of mass %, C at 0.040 to 0.10%, Si at not more than 0.3%, Mn at 1.7 to 2.5%, P at not more than 0.030%, S at not more than 0.005%, Al at not more than 0.1% and N at 0.006 to 0.025%, with the balance being represented by Fe and inevitable impurities, and has a microstructure in which a bainite phase represents not less than 60% on an area ratio basis, a total of a ferrite phase and a pearlite phase represents not more than 10% on an area ratio basis, and the bainite phase includes grains among which cementite grains have been precipitated at not less than 1.4×104 grains/mm2 and the cementite grains have an average grain diameter of not more than 1.5 μm. |
地址 |
JP |