Effect of cold rolling on annealing behavior and retained austenite characteristics of multiphase cmnsi steel

Abstract

The newly developed multiphase transformation-induced plasticity (TRIP steels are of interest for industrial applications because of their excellent combination of high strength and ductility. Retained austenite as a key constituent in final microstructure plays an important role in TRIP steels. The volume fraction, carbon concentration, size and morphology of this phase are the well known parameters which effects on the rate of transformation of retained austenite to martensite and the properties of steel. The performance of steel can be successfully controlled by designing an optimum balance in the volume fractions of ferrite, bainite and retained austenite. Against this background, in this research the effect of initial cold-rolling reduction and intercritical annealing temperature on the final microstructure and retained austenite characteristics has been studied on a silicon-containing TRIP steel by electron backscattered diffraction (EBSD) method. The results show that moderate percent of cold rolling followed by intermediate annealing temperature would provide optimum condition for desirable retained austenite characteristics with proper adjacent phase. © 2013 ISIJ.