Low-alloy duplex, directly quenched transformation-induced plasticity steel

A duplex microstructure consisting of allotriomorphic ferrite and austenite at ambient temperature has been produced in a low-alloy steel by a simple heat treatment which involves intercritical annealing followed by quenching. The tensile properties obtained are good, with a total elongation of some 28% at an ultimate tensile strength approaching 900 MPa. The form of the stress vs. strain curve is suitable for automotive applications, but it is speculated that the steel could be better exploited in a hot-pressed form.