Dual-phase hot-press forming alloy

Abstract

Hot-press forming steels are formed in a fully austenitic state followed by die-quenching in order to generate martensite and achieve strong steel. The ductility however, tends to be limited. We explore in this work a novel steel design in which the forming operation is in the two-phase austenite and ferrite field, so that the quenching results in a dual-phase ferrite and martensite microstructure at ambient temperature. It is demonstrated that better properties are achieved. The interpretation of the mechanisms of deformation during tensile testing indicates that the ductility can be further enhanced without compromising strength. The new steel also can be heated to temperature which is lower than that used for conventional hot-press forming steels, before transfer into the forming press. (C) 2010 Elsevier B.V. All rights reserved.