Possibilities for Microstructural Control During Hot Working of Austenitic Stainless Steels

The development of fine-grained microstructures by hot working to strains sufficient to effect at least partial dynamic recrystallization has been investigated by hot compression experiments on two austenitic stainless steels. After deformation, specimens were either held at the working temperature or cooled at a constant rate. As expected, fine structures are produced after working at low temperatures but, unfortunately, these tend to be mixed, the smaller grains originating from dynamic recrystallization and the coarser from static (metadynamic) recrystallization during holding/cooling. This heterogeneity is less pronounced after working at higher temperatures and, for given deformation conditions, tends to be eliminated as the cooling rate is reduced.