公开(公告)号：US20230002847A1

公开(公告)日：2023-01-05

申请号：US17784848

申请日：2020-12-16

Applicant: ArcelorMittal

Inventor： Astrid PERLADE ,  Kangying ZHU ,  Coralie JUNG ,  Frederic KEGEL

IPC: C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: A cold rolled and heat-treated steel sheet having a composition including, by weight percent C: 0.12-0.25% Mn: 3.0-8.0%, Si: 0.70-1.50%, Al: 0.3-1.2%, B: 0.0002-0.004%, S≤0.010%, P≤0.020%, N≤0.008%, the remainder of the composition being iron and unavoidable impurities resulting from the smelting, and having a microstructure consisting of, in surface fraction: between 5% and 45% of ferrite, between 25% and 85% of partitioned martensite, the partitioned martensite having a carbides density strictly less than 2×106/mm2, between 10% and 30% of retained austenite, less than 8% of fresh martensite, a part of the fresh martensite being combined with retained austenite in the shape of martensite-austenite islands in total surface fraction less than 10%.

公开(公告)号：US20200347471A1

公开(公告)日：2020-11-05

申请号：US16765207

申请日：2018-11-21

Applicant: ArcelorMittal

Inventor： Kangying ZHU ,  Astrid PERLADE ,  Coralie JUNG ,  Frederic KEGEL

IPC: C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C23C2/06 ,  C23C2/12 ,  B23K20/12

Abstract: A cold-rolled and heat-treated steel sheet having a microstructure of, in surface fraction: between 10% and 30% of retained austenite, said retained austenite being present as films having an aspect ratio of at least 3 and as Martensite Austenite islands, less than 8% of such Martensite Austenite islands having a size above 0.5 μm, at most 10% of fresh martensite and recovered martensite containing precipitates of at least one element chosen among niobium, titanium and vanadium. A manufacturing method thereof is also provided.

公开(公告)号：US20230027001A1

公开(公告)日：2023-01-26

申请号：US17784812

申请日：2020-12-17

Applicant: ArcelorMittal

Inventor： Astrid PERLADE ,  Kangying ZHU ,  Coralie JUNG ,  Frederic KEGEL

IPC: C22C38/04 ,  C22C38/02 ,  C22C38/26 ,  C22C38/28 ,  C22C38/22 ,  C22C38/06 ,  C22C38/38 ,  C21D8/02

Abstract: A hot rolled steel sheet having a composition including, by weight percent:C:0.10-0.25%, Mn:3.5-5.0%, Si:0.80-1.60%, B:0.0003-0.004%, S≤0.010%, P≤0.020%, N≤0.008% the remainder of the composition being iron and unavoidable impurities resulting from the smelting, and having a microstructure consisting of, in surface fraction: between 50% and 80% of lath bainite, lower than 30% of granular bainite, the rest being martensite, martensite-austenite islands and austenite films, and having less than 20% of martensite and M-A islands having the multiplication of the maximum length Lmax of the grain by the maximum width Wmax of the grain higher than 1 μm2.

公开(公告)号：US20200370141A1

公开(公告)日：2020-11-26

申请号：US16766328

申请日：2018-11-21

Applicant: ArcelorMittal

Inventor： Kangying ZHU ,  Astrid PERLADE ,  Coralie JUNG ,  Frederic KEGEL

IPC: C21D9/46 ,  B32B15/01 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C21D1/18 ,  B23K11/11 ,  B23K11/16

Abstract: A cold-rolled and heat-treated steel sheet-having a microstructure consisting of, in surface fraction: between 10% and 30% of retained austenite, said retained austenite being present as films having an aspect ratio of at least 3 and as Martensite Austenite islands, less than 8% of such Martensite A islands having a size above 0.5 μm, at most 1% of fresh martensite at most 50% of tempered martensite and recovered martensite containing precipitates of at least one element chosen among niobium, titanium and vanadium. It also provides a manufacturing method thereof.