Development of dynamic recrystallization maps based on the initial grain size

A series of hot compression tests at the temperature range of 900-1100 degrees C and strain rate of 0.01-1 s(-1) was carried out using a 304L stainless steel with different initial grain sizes. The hot deformation flow curves, the corresponding strain hardening curves, and the resulting microstructures were analyzed in order to reveal the occurrence of dynamic recrystallization (DRX). Results showed that despite the shape of flow curves, DRX occurs in the range of deformation conditions examined in the current work. Some DRX maps were developed by considering the effect of initial grain size and deformation conditions. These maps showed that the effect of austenite grain size on the progress of DRX in the temperature-strain rate coordinate is considerable and should be taken into account in thermomechanical processing. Since the occurrence and the extent of static and metadynamic recrystallization highly depend on the completion of DRX during deformation, the full DRX maps based on grain size can be used to find the appropriate working conditions based on the desired microstructures in the hot deformation schedules, especially in the dynamic recrystallization controlled rolling. (C) 2012 Elsevier B.V. All rights reserved.