Effect of Cr additions on ferrite recrystallization and austenite formation in dual-phase steels heat treated in the intercritical temperature range

Abstract

An experimental investigation was conducted using laboratory-processed low carbon Mn-Mo-Nb-Ti-B dual phase steel with additions of 0.2Cr or 0.6%Cr. This study investigates the effect of Cr additions on ferrite recrystallization and austenite formation during continuous annealing in the intercritical temperature range. It was found that moderate additions of Cr (0.2%) accelerates the ferrite recrystallization (nucleation and growth) resulting in coarse ferrite grains. An increase in Cr content up to 0.6% also accelerates the ferrite recrystallization which in addition to the presence of Cr-rich carbides facilitates the austenitization predominantly through the nucleation process resulted in fifiner austenite grains. Thereby, the higher Cr content increases the volume of homogenized and refifined martensite in the final quenched structure.