Influence of Direct Annealing Heat Treatment on the Mechanical Properties of As-Casting TWIP Steels

The effect of direct annealing on the mechanical properties of twinning-induced plasticity (TWIP) steel as casting condition has been investigated in this work. The results show that the UTS increased by about 50 MPa, from 350 to 400 MPa after direct annealing heat treatment; while elongation increased from 9 to 19%. The increasing of UTS after direct annealing heat treatment can be attributed to the precipitation strengthening effect and twinning-induced plasticity effect. The decrease in SFE of the austenite matrix also plays an important roll on the tensile properties of present TWIP steels in this study.