Effect of rolling temperature on the deformation and recrystallization textures of warm-rolled steels

Abstract

Warm-rolling trials were carried out on three interstitial-free (IF) steels (stabilized with either niobium or titanium), an extralow-carbon (ELC) steel, and an experimental low-carbon chromium (LC Cr) material at temperatures between 440 °C and 850 °C. The influence of rolling temperature on their as-rolled microstructures and deformation and recrystallization textures was investigated. Also, the effect of coiling simulation and degree of rolling reduction on the r values of some of these materials was examined. In-grain shear bands were evident in all as-rolled microstructures, but their sensitivity to deformation temperature varied between steels. Shear bands of moderate intensity were formed in the IF steels across all temperatures. In the ELC material, intense shear bands were formed at low rolling temperatures, but at higher temperatures, this intensity was drastically reduced. The development of shear bands at the higher rolling temperatures was significantly enhanced by alloying with chromium. The deformation textures produced were typical of rolled ferrite materials. The intensity of this texture increased markedly with temperature for the ELC grade. Conversely, the intensity of the recrystallization texture decreased with increasing temperature. The addition of chromium was found to strengthen the {111} component and, hence, the formability. The sharpness of both the deformation and recrystallization textures of the IF steels was relatively unaffected by rolling temperature. These differences are attributed to the intensity and frequency of shear-band formation and the dynamic strain-aging (DSA) behaviors of the various materials.