Effect of strain path change on texture and microstructure evolution in asymmetric rolled extra-low carbon steel

In asymmetric rolling, it is possible to introduce a shear strain component in the bulk of the sheet. In this work, the rolling sequence was changed in alternate passes by rotating the sheet about its three axes: the rolling, transverse and normal directions. Depending on the strain path, the shear component can be increased or even be cancelled. The objective of changing the strain path is to investigate the consequences of the varying imparted shear introduced by the asymmetric rolling on the deformed microstructure and the texture evolution. Comparisons were made with respect to the monotonic rolling case. It has been found that when the strain path change is reducing the shear, there are more differences in the microstructure with monotonic rolling than in shear-reinforcement strain path sequence. The texture evolution as well as the grain boundary characteristics are also very sensitive to the strain path. Severe rolling was examined up to 99% rolling reduction. It has been found that there was an increase in the average grain size in the 95%-99% rolling stage. This effect can be related to the texture-evolution induced grain coarsening phenomenon.