公开(公告)号：US20170152579A1

公开(公告)日：2017-06-01

申请号：US15322829

申请日：2015-07-03

Applicant: ArcelorMittal

Inventor： Rashmi Ranjan Mohanty ,  Hyun Jo Jun ,  Dongwei Fan

IPC: C21D9/46 ,  C21D1/18 ,  B32B15/01 ,  C22C38/06 ,  C23C2/06 ,  C23C2/40 ,  C22C38/58 ,  C22C38/02 ,  C21D8/02 ,  C23C2/02

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D1/18 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C21D2211/001 ,  C21D2211/008 ,  C22C38/02 ,  C22C38/06 ,  C22C38/34 ,  C22C38/38 ,  C22C38/58 ,  C23C2/02 ,  C23C2/06 ,  C23C2/40

Abstract: A method for producing a high strength coated steel sheet having a yield stress YS>800 MPa, a tensile strength TS>1180 MPa, and improved formability and ductility. The steel contains: 15%≦C≦0.25%, 1.2%≦Si≦1.8%, 2%≦Mn≦2.4%, 0.1% 23 Cr≦0.25%, Al≦0.5%, the remainder being Fe and unavoidable impurities. The sheet is annealed at a temperature higher than Ac3 and lower than 1000° C. for a time of more than 30 s, then quenched by cooling it to a quenching temperature QT between 250° C. and 350° C., to obtain a structure consisting of at least 60% of martensite and a sufficient austenite content such that the final structure contains 3% to 15% of residual austenite and 85% to 97% of martensite and bainite without ferrite, then heated to a partitioning temperature PT between 430° C. and 480° C. and maintained at this temperature for a partitioning time Pt between 10 s and 90 s, then hot dip coated and cooled to the room temperature.

公开(公告)号：US20170137906A1

公开(公告)日：2017-05-18

申请号：US15316600

申请日：2015-06-03

Applicant: ArcelorMittal

Inventor： Dongwei Fan ,  Hyun Jo Jun ,  John A. Rotole

IPC: C21D9/46 ,  C23C2/06 ,  C23C2/02 ,  C23C2/40 ,  C23C2/28 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/24 ,  C22C38/22 ,  C22C38/02 ,  C22C38/06 ,  C22C38/00 ,  C21D8/02

Abstract: The invention deals with a cold rolled and hot dip steel sheet, with a tensile strength of at least 980 MPa, with yield strength above or equal to 500 MPa, with total elongation above or equal to 8%, the composition consisting by weight percent: 0.05

公开(公告)号：US20170130292A1

公开(公告)日：2017-05-11

申请号：US15322947

申请日：2015-07-03

Applicant: ArcelorMittal

Inventor： Rashmi Ranjan Mohanty ,  Hyun Jo Jun ,  Dongwei Fan

IPC: C21D9/46 ,  C21D1/26 ,  C21D1/25 ,  C22C38/06 ,  C22C38/02 ,  C22C38/28 ,  C22C38/26 ,  C21D6/00 ,  C22C38/38

CPC classification number: C21D9/46 ,  C21D1/19 ,  C21D1/25 ,  C21D1/26 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0247 ,  C21D8/0447 ,  C21D9/48 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/008 ,  C22C38/02 ,  C22C38/06 ,  C22C38/26 ,  C22C38/28 ,  C22C38/34 ,  C22C38/38

Abstract: A method for producing a high strength steel sheet having a yield strength YS of at least 850 MPa, a tensile strength TS of at least 1180 MPa, a total elongation of at least 14% and a hole expansion ratio HER of at least 30%. The chemical composition of the steel contains: 0.15%≦C≦0.25%, 1.2%≦Si≦1.8%, 2%≦Mn≦2.4%, 0.1%≦Cr≦0.25%, Nb≦0.05%, Ti≦0.05%, Al≦0.50%, the remainder being Fe and unavoidable impurities. The sheet is annealed at an annealing temperature TA higher than Ac3 but less than 1000° C. for more than 30 s, by cooling it to a quenching temperature QT between 275° C. and 325° C., at a cooling speed sufficient to have, just after quenching, a structure consisting of austenite and at least 50% of martensite, the austenite content en.) 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, heated to a partitioning temperature PT between 420° C. and 470° C. and maintained at this temperature for time between 50 s and 150 s and cooled to the room temperature.

公开(公告)号：US12084738B2

公开(公告)日：2024-09-10

申请号：US16064513

申请日：2016-12-21

Applicant: ArcelorMittal

Inventor： Hyun Jo Jun ,  Pavan Venkatasurya

IPC: C21D9/46 ,  B32B15/01 ,  B32B15/18 ,  C21D1/22 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/26 ,  C23C2/00 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

CPC classification number: C21D9/46 ,  B32B15/013 ,  B32B15/18 ,  C21D1/22 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/02 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C22C38/001 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/26 ,  C23C2/00 ,  C23C2/0224 ,  C23C2/06 ,  C23C2/28 ,  C23C2/29 ,  C23C2/40 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008

Abstract: A method produces a steel sheet having a microstructure including, in area fraction, 20% to 50% intercritical ferrite, 10% to 20% retained austenite, 25% to 45% tempered martensite, 10% to 20% fresh martensite, and bainite. The sum of tempered martensite and bainite is between 30% and 60%. A cold-rolled steel sheet provided includes 0.18% ≤C≤0.25%, 0.9% ≤Si≤1.8%, 0.02% ≤Al≤1.0%, with 1.00% ≤Si+Al≤2.35%, 1.5% ≤Mn≤2.5%, 0.010% ≤Nb ≤0.035%, 0.10% ≤Cr≤0.40%. The steel sheet is annealed to obtain 50% to 80% austenite and 20% to 50% of ferrite, quenched at a cooling rate between 20° C/s and 50° C/s to between Ms-50° C. and Ms-5° C., heated to a partitioning temperature between 375° C. and 450° C. and maintained at the partitioning temperature for at least 50s, then immediately cooled to room temperature.

公开(公告)号：US11198928B2

公开(公告)日：2021-12-14

申请号：US16685315

申请日：2019-11-15

Applicant: ArcelorMittal

Inventor： Hyun Jo Jun ,  Narayan S. Pottore ,  Nina Michailovna Fonstein

IPC: C22C38/12 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C21D9/40

Abstract: A method for producing a dual phase steel sheet is provided. The method includes providing a dual phase hot rolled steel sheet having a microstructure including ferrite and martensite and a composition including 0.1 to 0.3 wt. % C, 1.5 to 2.5 wt. % Si and 1.75 to 2.5 wt. % Mn. The steel sheet is annealed at a temperature from 750 to 875° C., water quenched to a temperature from 400 to 420° C. and subject to overaging at the temperature from 400 to 420° C. to convert the martensite in the hot rolled steel sheet to tempered martensite. The overaging is sufficient to provide the hot rolled steel sheet with a hole expansion ratio of at least 15%.

公开(公告)号：US20210095357A1

公开(公告)日：2021-04-01

申请号：US17247358

申请日：2020-12-08

Applicant: ARCELORMITTAL

Inventor： Dongwei Fan ,  Hyun Jo Jun ,  Rashmi Ranjan Mohanty

IPC: C21D9/46 ,  C21D8/04 ,  C21D8/02 ,  C21D1/19 ,  B32B15/01 ,  C21D6/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

Abstract: A coated steel sheet includes a chemical composition including in weight %: 0.13%≤C ≤0.22%; 1.2%≤Si≤1.8%; 1.8%≤Mn≤2.2%; 0.10%≤Mo≤0.20%; Nb≤0.05%; Al≤0.5%; Ti≤0.05%; and a remainder being Fe and unavoidable impurities. A structure of the steel sheet consists of, by volume fraction, 3% to 15% of residual austenite and 85% to 97% of martensite and bainite. The structure includes at least 65% of martensite and does not including ferrite. At least one face of the coated steel sheet includes a metallic coating. The steel sheet has a yield strength of at least 800 MPa, a tensile strength of at least 1180 MPa, a total elongation of at least 14% and a hole expansion ratio HER of at least 30%.

公开(公告)号：US10954580B2

公开(公告)日：2021-03-23

申请号：US16064545

申请日：2016-12-21

Applicant: ArcelorMittal

Inventor： Pavan Venkatasurya ,  Hyun Jo Jun

IPC: C21D9/46 ,  C21D8/02 ,  C22C38/06 ,  C22C38/60 ,  B32B15/01 ,  C21D1/18 ,  C21D6/00 ,  C22C38/02 ,  C22C38/04

Abstract: A method for producing a steel sheet having a microstructure including 71% to 91% martensite and bainite, 9% to 13% retained austenite, and at most 20% ferrite is provided. The method includes providing a cold-rolled steel sheet including, in weight percent: 0.13%≤C≤0.22%, 1.2%≤Si≤2.3%, 0.02%≤Al≤1.0%, with 1.25%≤Si+Al≤2.35%, 2.4%≤Mn≤3%, Ti≤0.05%, Nb≤0.05% and a remainder of Fe and unavoidable impurities, annealing the steel sheet to obtain 80% to 100% austenite and 0% to 20% ferrite, quenching the steel sheet at a cooling rate between 20° C./s and 50° C./s to a quenching temperature between 240° C. and 310° C., heating the steel sheet to a partitioning temperature between 400° C. and 465° C. and maintaining the steel sheet at the partitioning temperature for 50 to 250 seconds, then immediately cooling the sheet to room temperature. Steel sheets are also provided.

公开(公告)号：US20190256942A1

公开(公告)日：2019-08-22

申请号：US16398873

申请日：2019-04-30

Applicant: ArcelorMittal

Inventor： Dongwei Fan ,  Hyun Jo Jun ,  John A. Rotole

IPC: C21D9/46 ,  C23C2/28 ,  B32B15/01 ,  C22C38/24 ,  C21D8/02 ,  C23C2/40 ,  C23C2/12 ,  C22C38/22 ,  C22C38/08 ,  C22C38/04 ,  C22C38/00 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/02 ,  C23C2/06 ,  C23C2/02

Abstract: A method for producing a cold rolled and hot dip coated steel sheet is provided. The method includes casting a steel into a slab, reheating, hot rolling, cooling, coiling, descaling and cold rolling the slab. The cold rolled steel sheet is annealed so a layer of iron oxide forms on the surface with an internal oxidation underneath. The sheet is then heated so the surface is oxidized and the layer of iron oxide is fully reduced to obtain an internally oxidized depth between 200 nm and 100 μm which includes one or more of Si, Mn, Al, Ti containing oxides. The sheet is then hot dip coated and cooled.

公开(公告)号：US11718888B2

公开(公告)日：2023-08-08

申请号：US16827696

申请日：2020-03-23

Applicant: ArcelorMittal

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

IPC: C21D9/46 ,  C22C38/04 ,  C22C38/02 ,  C21D8/02 ,  C21D1/18 ,  C21D6/00 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D9/00 ,  C21D8/00

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

Abstract: A method is for producing a high strength coated steel sheet having an improved ductility and an improved formability, and a chemical composition containing: 0.13%≤C≤0.22%, 1.9%≤Si≤2.3%, 2.4%≤Mn≤3%, Al≤0.5%, Ti≤0.05%, Nb≤0.05%, the remainder being Fe and unavoidable impurities. The sheet is annealed at temperature TA higher than Ac3 but less than 1000° C. for a time of more than 30 s, quenched by cooling to a quenching temperature QT between 200° C. and 280° C. in order to obtain 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, heated up to a partitioning temperature PT between 430° C. and 490° C. and maintained at this temperature for a time Pt between 10 s and 100 s, hot dip coated and cooled to the room temperature.

公开(公告)号：US11661637B2

公开(公告)日：2023-05-30

申请号：US17083451

申请日：2020-10-29

Applicant: ArcelorMittal

Inventor： Hyun Jo Jun

IPC: C21D9/46 ,  C21D8/02 ,  C23C2/06 ,  C23C2/28 ,  C21D1/20 ,  C21D1/25 ,  C23C2/02 ,  B32B15/01 ,  C21D6/00 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/12 ,  C22C38/26 ,  C22C38/38 ,  C23C2/40

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D1/20 ,  C21D1/25 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/06 ,  C22C38/12 ,  C22C38/26 ,  C22C38/38 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008

Abstract: A method for forming a cold rolled, coated and post batch annealed steel sheet is provided. The method includes cold rolling a steel sheet; coating the cold rolled steel sheet with a zinc or zinc alloy coating, the cold rolled, coated steel sheet having an initial hole expansion and an initial yield strength and post batch annealing the cold rolled, coated steel sheet at a tempering temperature in a range from 150 to 650° C., the post batch annealed steel sheet having a final hole expansion and a final yield strength. The steel sheet includes (in wt. %)C-0.1-0.3%, Mn-1-3%, Si-0.5-3.5%, Al-0.05-1.5% and Mo+Cr being between 0-1.0%. The final hole expansion is at least 80% greater than the initial hole expansion and the final yield strength is at least 30% greater than the initial yield strength.