公开(公告)号：US20230193412A1

公开(公告)日：2023-06-22

申请号：US18108533

申请日：2023-02-10

Applicant: ArcelorMittal

Inventor： Maya GOSPODINOVA ,  Véronique HEBERT

IPC: C21D8/02 ,  B23K11/11 ,  B23K35/30 ,  C22C38/04 ,  C22C38/22 ,  C22C38/26 ,  C22C38/34 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

CPC classification number: C21D8/0236 ,  B23K11/11 ,  B23K35/3073 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0263 ,  C22C38/04 ,  C22C38/22 ,  C22C38/26 ,  C22C38/34 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  B23K2103/04

Abstract: A method for producing a coated steel sheet having a tensile strength TS of at least 1100 MPa, a total elongation TE according to ISO standard 6892-1 of at least 12%, the product TS×TE of the tensile strength by the total elongation being at least 14200 MPa %, and a hole expansion ratio HER according to ISO standard 16630:2009 of at least 25%, the method including the following successive steps:



providing a cold-rolled steel sheet, the chemical composition of the steel containing in weight %: 0.15%≤C≤0.23%, 2.0%≤Mn≤2.7%, with C+Mn/10≥0.420%, 0≤Cr≤0.40%, with Mn+Cr≥2.25%, 0.2%≤Si≤1.6%, 0.02%≤Al≤1.2%, with 1.0%≤Si+Al≤2.2%, 0≤Nb≤0.035%≤Mo≤0.1%, the remainder being Fe and unavoidable impurities,
annealing the steel sheet at an annealing temperature TA so as to obtain a structure comprising at least 65% of austenite and at most 35% of intercritical ferrite,
quenching the sheet from a temperature of at least 600° C. at a cooling rate comprised between 20° C./s and 50° C./s down to a quenching temperature QT between 200° C. and 270° C.,
heating the sheet up to a partitioning temperature PT comprised between 400° C. and 480° C. and maintaining the sheet at this partitioning temperature PT for a partitioning time Pt comprised between 50 s and 250 s,
hot-dip coating the sheet at a temperature less than 515° C.,
cooling the coated sheet down to the room temperature,

the steel sheet having a microstructure consisting of, in surface fraction: between 3% and 15% of retained austenite, at least 30% of tempered martensite, at most 5% of fresh martensite, at most 35% of bainite, the sum of the surface fractions of tempered martensite, fresh martensite and bainite being comprised between 55% and 92%, and between 5% and 35% of ferrite.

公开(公告)号：US20240352573A1

公开(公告)日：2024-10-24

申请号：US18701735

申请日：2022-09-05

Applicant: ArcelorMittal

Inventor： Daniel CHALEIX ,  Véronique HEBERT ,  Fabrice LAFFINEUR ,  Vincent RUWET

IPC: C23C14/24 ,  C21D1/76 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C22C38/38 ,  C23C14/16

CPC classification number: C23C14/24 ,  C21D1/76 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0221 ,  C21D8/0247 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C22C38/38 ,  C23C14/16 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008

Abstract: A method for depositing metallic coatings on a substrate including an annealing step, in an annealing furnace, forming on said substrate, a ferritic surface layer having a thickness from 10 μm to 50 μm and a microstructure comprising in surface fraction up to 10% of cumulated amount of martensite, bainite and the balance being made of ferrite, a skin pass step, a coating step, inside a vacuum chamber, wherein a metallic vapour is ejected towards at least a side of said substrate to form a surface layer of at least one metal.

公开(公告)号：US20200270713A1

公开(公告)日：2020-08-27

申请号：US16063740

申请日：2016-12-21

Applicant: ArcelorMittal

Inventor： Maya GOSPODINOVA ,  Véronique HEBERT

IPC: C21D8/02 ,  C22C38/22 ,  C22C38/34 ,  C22C38/26 ,  C22C38/04 ,  C23C2/06 ,  C23C2/40 ,  C23C2/28 ,  B23K35/30 ,  B23K11/11

Abstract: A method for producing a coated steel sheet having a tensile strength TS of at least 1100 MPa, a total elongation TE according to ISO standard 6892-1 of at least 12%, the product TSxTE of the tensile strength by the total elongation being at least 14200 MPa %, and a hole expansion ratio HER according to ISO standard 16630:2009 of at least 25%, the method including the following successive steps: providing a cold-rolled steel sheet, the chemical composition of the steel containing in weight %: 0.15%≤C≤0.23%, 2.0%≤Mn≤2.7%, with C+Mn/10≥0.420%, 0≤Cr≤0.40%, with Mn+Cr≥2.25%, 0.2%≤Si≤1.6%, 0.02%≤Al≤1.2%, with 1.0%≤Si+Al≤2.2%, 0≤Nb≤0.035%, 0≤Mo≤0.1%, the remainder being Fe and unavoidable impurities, annealing the steel sheet at an annealing temperature TA so as to obtain a structure comprising at least 65% of austenite and at most 35% of intercritical ferrite, quenching the sheet from a temperature of at least 600° C. at a cooling rate comprised between 20° C./s and 50° C./s down to a quenching temperature QT between 200° C. and 270° C., heating the sheet up to a partitioning temperature PT comprised between 400° C. and 480° C. and maintaining the sheet at this partitioning temperature PT for a partitioning time Pt comprised between 50 s and 250 s, hot-dip coating the sheet at a temperature less than 515° C., cooling the coated sheet down to the room temperature, the steel sheet having a microstructure consisting of, in surface fraction: between 3% and 15% of retained austenite, at least 30% of tempered martensite, at most 5% of fresh martensite, at most 35% of bainite, the sum of the surface fractions of tempered martensite, fresh martensite and bainite being comprised between 55% and 92%, and between 5% and 35% of ferrite.

公开(公告)号：US20190003008A1

公开(公告)日：2019-01-03

申请号：US16064596

申请日：2016-12-20

Applicant: ARCELORMITTAL

Inventor： Maya GOSPODINOVA ,  Véronique HEBERT ,  Pavan VENKATASURYA

IPC: C21D9/46 ,  C22C38/26 ,  C22C38/06 ,  C22C38/38 ,  C22C38/34 ,  C22C38/22 ,  C21D8/02 ,  C21D6/00 ,  C21D1/18 ,  C23C2/06 ,  C23C2/40 ,  B32B15/01 ,  B23K11/11

Abstract: A method for producing a steel sheet is provided. The method includes providing a cold-rolled steel sheet including in weight %: 0.15%≤C≤0.23%, 1.4%≤Mn≤2.6%, 0.6%≤Si≤1.5%, 0.02%≤Al≤1.0%, with 1.0%≤Si+Al≤2.0%, 0≤Nb≤0.035%, 0≤Mo≤0.3%, 0≤Cr≤0.3%, and a remainder of Fe and unavoidable impurities, annealing the steel sheet at an annealing temperature between Ac1 and Ac3 to obtaining at least 40% austenite and at least 40% intercritical ferrite, quenching the sheet from at least 600° C. at a cooling rate of at least 20° C./s to a quenching temperature between 180° C. and 260° C., heating the sheet to a partitioning temperature between 375° C. and 470° C. and maintaining the sheet at this partitioning temperature for a partitioning time Pt between 25 s and 440 s, then cooling the sheet to room temperature. A steel sheet is also provided.

公开(公告)号：US20160312326A1

公开(公告)日：2016-10-27

申请号：US15102386

申请日：2014-12-05

Applicant: ARCELORMITTAL

Inventor： Josée DRILLET ,  Véronique HEBERT

IPC: C21D9/46 ,  C22C38/28 ,  C22C38/26 ,  C22C38/22 ,  C22C38/32 ,  C23C2/36 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C23C2/02 ,  C23C2/06 ,  C22C38/38 ,  C22C38/06

Abstract: A cold-rolled and annealed steel sheet is provided, the chemical composition of which comprises, the contents being expressed by weight percent: 0.10≦C≦0.13% 2.4≦Mn≦2.8% 0.30≦Si≦0.55% 0.30≦Cr≦0.56% 0.020≦Ti≦0.050% 0.0020≦B≦0.0040% 0.005≦Al≦0.050% Mo≦0.010% Nb≦0.040% 0.002≦N≦0.008% S≦0.005% P≦0.020%, the remainder consisting of iron and unavoidable impurities resulting from the smelting, the steel sheet having a microstructure consisting of, in surface proportion, martensite and/or lower bainite, said martensite comprising fresh martensite and/or self-tempered martensite, the sum of the surface proportions of martensite and lower bainite being comprised between 60 to 95%, 4 to 35% of low carbide containing bainite, 0 to 5% of ferrite, and less than 5% of retained austenite in island form.