公开(公告)号：US20240102138A1

公开(公告)日：2024-03-28

申请号：US18266682

申请日：2021-12-03

Applicant: ARCELORMITTAL

Inventor： Clément PHILIPPOT ,  Sandra LEGUILLARD ,  David DUSSAUSSOIS ,  Matthieu SALIB

IPC: C22C38/38 ,  B21C47/02 ,  C21D8/02 ,  C21D8/04 ,  C22C38/02 ,  C22C38/06 ,  C22C38/28 ,  C22C38/32 ,  C23C2/02 ,  C23C2/12 ,  C23C2/28 ,  C23C2/40

CPC classification number: C22C38/38 ,  B21C47/02 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0273 ,  C21D8/0278 ,  C21D8/0436 ,  C22C38/02 ,  C22C38/06 ,  C22C38/28 ,  C22C38/32 ,  C23C2/0224 ,  C23C2/12 ,  C23C2/29 ,  C23C2/40 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008

Abstract: A coated steel sheet and press hardened steel part having a composition including, by weight percent: C 0.26-0.40%, Mn 0.5-1.8%, Si 0.1-1.25%, Al 0.01-0.1%, Cr 0.1-1.0%, Ti 0.01-0.1%, B 0.001-0.004%, P 0.020%, S 0.010%, N 0.010% the remainder of the composition being iron and unavoidable impurities resulting from the smelting. The press hardened steel part includes a bulk having a microstructure including, in surface fraction, more than 95% of martensite and less than 5% of bainite, a coating layer at the surface of the steel part, a ferritic interdiffusion layer between the coating layer and the bulk, and a ratio between the ferritic grain width in the interdiffusion layer GWint over prior austenite grain size in the bulk PAGSbulk, satisfying following equation (GWint/PAGSbulk)−1≥30%.