公开(公告)号：US20220017985A1

公开(公告)日：2022-01-20

申请号：US17311808

申请日：2019-12-17

Applicant: ArcelorMittal

Inventor： Patrice ALEXANDRE ,  Magali BOUZAT ,  Anirban CHAKRABORTY ,  Hassan GHASSEMI-ARMAKI ,  Olga GIRINA ,  Ronan JACOLOT ,  Alexey KOLTSOV ,  Aude NADLER ,  Damon PANAHI ,  Michel SOLER

IPC: C21D9/46 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/22 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C21D1/18

Abstract: A cold rolled and heat-treated steel sheet having a composition including, by weight percent: C 0.3-0.4%, Mn 2.0-2.6%, Si: 0.8-1.6%, Al 0.01-0.6%, Mo 0.15-0.5%, Cr 0.3-1.0%, Nb≤0.06%, Ti≤0.06%, Ni≤0.8%, S≤0.010%, P≤0.020% and 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 15% and 30% of retained austenite, said retained austenite having a carbon content of at least 0.7%, between 70% and 85% of tempered martensite, at most 5% of fresh martensite and at most 5% of bainite. It also deals with a manufacturing method thereof.

公开(公告)号：US20240287638A1

公开(公告)日：2024-08-29

申请号：US18573247

申请日：2021-07-16

Applicant: ArcelorMittal

Inventor： Pierrick FORT ,  Aude NADLER ,  Kangying ZHU ,  Astrid PERLADE ,  Michel SOLER ,  Frédéric KEGEL

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

CPC classification number: C21D9/46 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2261/00

Abstract: A process for manufacturing a steel part, including the following successive steps: providing a steel sheet having a composition including by weight percent: C: 0.05—0.25%, Mn: 3.5-8%, Si 0.1-2%, Al: 0.01-3%, 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, in surface fraction, between 10% and 50% of retained austenite, 50% or more of the sum of ferrite, bainite and tempered martensite, less than 5% of fresh martensite, less than 2% of carbides and a carbon [C]A content in austenite, strictly more than 0.4% and strictly less than 0.7%, cutting the steel sheet to a predetermined shape, to obtain a steel blank, heating the steel blank to a temperature Twarm from (Md30-150° C.) to (Md30-50° C.), punching or shearing and forming the heat-treated steel blank at the Twarm temperature to obtain a steel part.