Rolled steel that hardens by means of precipitation after hot-forming and/or quenching with a tool having very high strength and ductility, and method for manufacturing same

US9689050B2 · kind B2 · utility

Assignee

• ARCELORMITTAL INVESTIGACIÓN Y DESARROLLO, S.L. · ES

Inventors

• Olivier Bouaziz · Metz, FR
• David BARBIER · Grenoble, FR
• Coralie Jung · Racrange, FR

Key dates

• Filing date: Sep 6, 2011
• Grant date: Jun 27, 2017
• Expiry date: Aug 24, 2032

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/12799
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A rolled steel sheet or blank is provided, the composition of which comprises the elements listed below in percent by weight: C≦0.1%; 0.5%≦Mn≦7%; 0.5%≦Si≦3.5%; 0.5%<Ti≦2%; 2%<Ni≦7%; Al≦0.10%; Cr≦2%; Cu≦2%; Co≦2%; Mo≦2%; S≦0.005%; P≦0.03%; Nb≦0.1%; V≦0.1%; B<0.005%; N≦0.008%, and the silicon and titanium contents are such that:the remainder of the composition consisting of iron and unavoidable impurities resulting from processing. A method for the fabrication of a part for a land motor vehicle from the sheet or blank by hot stamping is also provided. The microstructure of the part consisting essentially of martensite and intermetallic precipitates of type Fe2TiSi with an area percentage between 1 and 5% intermetallic precipitates.