Effect of re-austenitization on the transformation texture inheritance

Abstract

Bainitic-martensitic microstructures produced by direct quenching austenite subjected to different degrees of pancaking have been re-austenitized and quenched to fully martensitic structures in order to investigate the effect of prior texture on the final martensite texture. Three different prior austenite pancaking states varying from convex-like to highly pancaked were investigated using an ultrahigh-strength strip steel hot rolled with various finish rolling temperatures followed by direct quenching. Microstructures were characterized using FESEM and transformation texture analysed using FESEM-EBSD at the strip surface, quarter- thickness and mid-thickness positions. The results show that an increase in rolling reduction below the non-recrystallization temperature increases the intensities of ∼{554}<225> α and ∼{112}<110> α texture components in the ferrite along the strip mid-thickness and of the ∼{112}<111> α component at the surface. The re-austenitization of the materials at 910°C for 30 min led to an inheritance of the same components from the parent specimens, but also increased the intensity of {001}<110> α, {110}<110> α and {011}<100> α components.