发明名称 |
High strength steel sheet and method for manufacturing the same |
摘要 |
A high strength steel sheet has tensile strength of at least 1470 MPa and (tensile strength ×total elongation) of at least 29000 MPa·% with a composition including, by mass %, C.: 0.30% to 0.73%, Si: 3.0% or less, Al: 3.0% or less, Si+Al: at least 0.7%, Cr: 0.2% to 8.0%, Mn: 10.0% or less, Cr+Mn: at least 1.0%, P: 0.1% or less, S: 0.07% or less, N: 0.010% or less, and remainder as Fe and incidental impurities; and processing the steel sheet such that microstructure satisfies area ratio of martensite with respect to the microstructure of 15% to 90%; content of retained austenite of 10% to 50%; at least 50% of the martensite is constituted of tempered martensite and area ratio of the tempered martensite with respect to the microstructure is at least 10%; and area ratio of polygonal ferrite with respect to the microstructure is 10% or less. |
申请公布号 |
US9200343(B2) |
申请公布日期 |
2015.12.01 |
申请号 |
US201113583013 |
申请日期 |
2011.02.28 |
申请人 |
JFE Steel Corporation |
发明人 |
Matsuda Hiroshi;Funakawa Yoshimasa;Tanaka Yasushi |
分类号 |
C21D1/22;C21D6/00;C21D8/02;C21D9/46;C22C38/00;C22C38/02;C22C38/04;C22C38/06;C22C38/18;C22C38/20;C22C38/22;C22C38/24;C22C38/26;C22C38/28;C22C38/32;C22C38/34;C22C38/38;C22C38/40;C22C38/58;C23C2/02;C23C2/28;B32B15/01 |
主分类号 |
C21D1/22 |
代理机构 |
DLA Piper LLP (US) |
代理人 |
DLA Piper LLP (US) |
主权项 |
1. A high strength steel sheet having a tensile strength of at least 1470 MPa and (tensile strength (TS)×total elongation (T. EL)) of at least 29000 MPa·%, comprising a composition including by mass %,
C: 0.55% to 0.73%, Si: 3.0% or less, Al: 3.0% or less, Si+Al: at least 0.7%, Cr: 0.2% to 8.0%, Mn: 10.0% or less, Cr+Mn: at least 1.0%, P: 0.1% or less, S: 0.07% or less N: 0.010% or less, and remainder as Fe and incidental impurities,and having a microstructure satisfying conditions: area ratio of martensite with respect to the entire microstructure of 15% to 90%; content of retained austenite of 10% to 50%, wherein at least 50% of said martensite is constituted of tempered martensite and an area ratio of said tempered martensite with respect to the entire microstructure of the steel sheet is at least 10%; and an area ratio of polygonal ferrite with respect to the entire microstructure of the steel sheet is 10% or less,
wherein average carbon concentration in said retained austenite is at least 0.7mass %. |
地址 |
JP |