公开(公告)号：US20230120827A1

公开(公告)日：2023-04-20

申请号：US17905827

申请日：2021-03-11

申请人： JFE STEEL CORPORATION

发明人： Thihuyen DOAN ,  Sota GOTO ,  Hiroshi HASEGAWA ,  Noriaki MORIYASU ,  Takanori UMINO ,  Takeshi UEDA

IPC分类号： C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C21D8/02 ,  B21C47/02

摘要： Provided is a high strength steel sheet that has a tensile strength of 1180 MPa or more and a uniform elongation of 6 % or more. The high strength steel sheet has a chemical composition that contains predetermined components with a MSC of 3.0 mass% to 4.2 mass%. The high strength steel sheet has a microstructure including upper bainite in an area fraction of 70 % or more as a main phase, fresh martensite and retained austenite in a total area fraction of 7 % to 30 %, with the retained austenite having an area fraction of 2 % or more. The high strength steel sheet has a mechanical property with a uniform elongation of 6 % or more and a tensile strength of 1180 MPa or more.