Properties assessment of the first industrial coils of low-density duplex δ-TRIP steel

Abstract

A novel low-density steel with high aluminium content was, for the first time, manufactured as coils by the conventional industry process consisting of continuous casting followed by hot-rolling and cold-rolling. The duplex δ-TRIP microstructure, comprising a mixture of blocky retained austenite and both δ- and α-ferrite, was then produced by laboratory-scale heat treatments. The microstructure generation was achieved by an intercritical annealing followed by direct quenching, which was the same process as that for producing conventional dual-phase steels. The alloy exhibits quite interesting mechanical properties with a combination of 930 MPa tensile strength and of 21% total elongation, both in rolling and transverse directions. The formability of this novel alloy was assessed and discussed.