Multi-pass rolling was carried out on extra-low carbon steel at room temperature by imposing different ratios of asymmetry in the roll-diameters as well as by conventional mode. The aim of this study is to understand the effect of shear deformation due to the asymmetric conditions on the development of the rolling texture and the possibilities of propagating the shear deformation into the mid-thickness area of the sheet. The trends of the measured texture developments in both symmetric and asymmetric rolling indicate their dependence primarily on the stability and fraction of the Goss {110} and the rotated cube {001} orientations. The effects of asymmetry conditions were further examined on the microstructure evolution and were correlated to the increased orientation inhomogeneity and grain fragmentation. Both texture and microstructure development showed their dependence on the applied thickness reduction per pass, on the total thickness reduction of the sheet as well as on the degree of the imposed asymmetry. It was found that shear textures can be obtained by asymmetric rolling at conditions where all three parameters—asymmetry ratio, strain in one pass, and the total accumulated strain—are as large as possible.

This study was carried out with medium carbon steel to investigate the austenite grain growth kinetics at three temperatures and the effect of prior austenite grain size on bainitic transformation kinetics. Grain growth behaviour of austenite with two initial microstructures, pearlite and bainite, have shown almost similar kinetics. The activation energy values were determined to be 79 and 95 kJ mol⁻¹ for bainitic and pearlitic microstructures, respectively. Prior austenite grain size has shown a strong effect on bainitic transformation kinetics. Higher the austenite grain size faster was the kinetics of bainitic transformation and an increase in the volume fraction of bainitic ferrite. The growth of bainite played the most important role in controlling the bainitic transformation kinetics.