Restoration processes during hot deformation in the delta-ferrite and austenite dual phase region of AISI430 ferritic stainless steel

The restoration mechanisms of AISI430 ferritic stainless steel under industrial rolling conditions (strain 0.6, strain rate 16 s-1) were studied experimentally. Dynamic recovery followed by static recrystallisation and concurrent static recovery were observed in the ferrite phase at the hot rolling temperature (960°C). Complete recrystallisation (>70%) was hindered by the impingement of the new grains on the widespread y phase and the extensive recovery. At lower strain rates, typical of nominal laboratory experiments, restoration through a more continuous process was observed, where recovery mechanisms were promoted by the longer deformation time. An explanation of the microstructural evolution of this material under hot rolling conditions and the interaction of these mechanisms is presented. © 2007 ISIJ