Structural evolutions and mechanical properties of IF steel deformed by differential speed rolling at various per-pass-thickness reductions

In the present work, the effects of thickness reduction per pass introduced by differential speed rolling (DSR)on microstructure and texture evolutions and related mechanical properties of interstitial-free (IF)steel samples were investigated. For this purpose, the samples were subjected to DSR deformation at various per-pass-thickness reductions; 10% (14 passes), 30% (4 passes), and 50% (2 passes). The results showed that the DSR deformation at a high thickness reduction per pass (50%)leads to ultrafine grained structure (∼0.5 μm)with significant fractions of high angle grain boundaries (HAGBs). This structure was conjugated with a high strength and low ductility as compared to those in the non-deformed sample.