Effect of intercritical annealing on the Luders strains of medium Mn transformation-induced plasticity steels

The present work systematically investigates the effects of starting microstructure and intercritical annealing temperature on the tensile properties and Luders strain of transformation-induced plasticity steels containing 5 wt.% Mn. It is found that higher intercritical annealing temperature leads to smaller Luders strain, lower yield strength and higher ultimate tensile strength. The starting cold-rolled microstructure produces much coarser microstructural constituents and larger Luders strain than the martensitic one. It is concluded that the fraction and size of austenite grains and the amount of carbide formed during intercritical annealing are the most important microstructural factors to determine the Luders strain rather than the fraction of retained austenite and the grain size of the ferritic phase. (C) 2015 Elsevier Ltd. All rights reserved.