公开(公告)号：US20170137908A1

公开(公告)日：2017-05-18

申请号：US15322789

申请日：2015-07-03

Applicant: ArcelorMittal

Inventor： Dongwei Fan ,  Hyun Jo Jun ,  Rashmi Ranjan Mohanty ,  Pavan K.C. Venkatasurya

IPC: C21D9/46 ,  C23C2/28 ,  C23C2/40 ,  C22C38/14 ,  C21D1/18 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C21D6/00 ,  C23C2/06 ,  C22C38/12

CPC classification number: C21D9/46 ,  C21D1/18 ,  C21D6/005 ,  C21D6/008 ,  C21D8/02 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C23C2/06 ,  C23C2/285 ,  C23C2/40

Abstract: A method for producing a high strength coated steel sheet having an improved ductility and an improved formability, the chemical composition of the steel containing: 0.13%≦C≦0.22%, 1.9%≦Si≦2.3%, 2.4%≦Mn≦3%, Al≦0.5%, Ti

公开(公告)号：US20170137907A1

公开(公告)日：2017-05-18

申请号：US15322712

申请日：2015-07-03

Applicant: ArcelorMittal

Inventor： Rashmi Ranjan Mohanty ,  Hyun Jo Jun ,  Dongwei Fan ,  Pavan K.C. Venkatasurya

IPC: C21D9/46 ,  C21D1/18 ,  C22C38/02 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C21D6/00 ,  C22C38/14

Abstract: A method for producing a high strength steel sheet having a yield strength YS>850 MPa, a tensile strength TS>1180 MPa, a total elongation >13% and a hole expansion ratio HER>30%, by heat treating a steel sheet wherein the chemical composition of the steel contains: 0.13%≦C≦0.22%, 1.2%≦Si≦1.8%, 1.8%≦Mn≦2.2%, 0.10%≦Mo≦0.20%, Nb≦0.05%, Ti 865° C. and 30° C./s in order to have, just after quenching, a structure consisting of austenite and at least 50% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85% and 97% of the sum of martensite and bainite without ferrite, then heated to a partitioning temperature PT between 370° C. and 470° C. and maintained at this temperature for a time Pt between 50 s and 150 s, then cooled to the room temperature