Bake-hardening behavior of cold-rolled CMnSi and CMnSiCu TRIP-aided steel sheets

The aim of this paper is to investigate the bake-hardening (BH) behavior of cold-rolled 0.2C–1.5Mn–1.5Si and 0.2C–1.5Mn–1.5Si–0.5Cu TRIP-aided steels. By analyzing the variation of the mechanical properties and microstructure of the two steels during paint baking, it is found that the BH values of both steels are about 25 MPa, and that some retained austenite changed into bainite during paint baking, copper addition has less influence on the BH value although, it leads to the increase of tensile strength.