Effect of hot working on dynamic recrystallisation study of as-cast austenitic stainless steel

Dynamic recrystallisation (DRX) behaviour of as-cast austenitic stainless steel strip is investigated in order to study the extent of DRX that could heavily refine the as-cast austenite prior to phase transformation. The specimens were very quickly heated to the deformation temperatures to ensure that there was little or no change to the as-cast structure in order to simulate accurately the microstructure evolution and recrystallisation behaviour of the cast strip on reheating in the thermomechanical testing system. This investigation will assist the generation of the fundamental knowledge required to develop advanced high strength and formable steels using thin strip/slab casting processes. The results reveal that DRX of the coarse austenite grains is a relatively slow process and austenite will be refined completely by DRX under high deformation temperature (1100-1200 degrees C) and slow strain rate (0.5-5 s(-1)) conditions. It is observed that new grains nucleate predominantly at the parent austenite grain boundaries and tend to form in clusters. (c) 2012 Elsevier B.V. All rights reserved.