Dynamic recrystallization of friction welded AISI 316 stainless steel joints

Abstract

The microstructural characteristics of friction welded AISI 316 stainless steel samples in a welding zone and a heat affected zone were investigated. Inhomogeneous plastic deformation occurred due to friction welding. Individual grains in the final microstructure underwent various evolution mechanisms. These were caused by the growth of the initially recrystallized grains or as a result of the dynamic recrystallization of the sub-grains formed. The grains within the welding zone and the heat affected zone exhibited different densities of dislocations and experienced various degrees of recovery. Using reasonable estimates of the strain, strain rate and temperature of the friction welding, the dependence of the dynamic recrystallization grain size was found to have the same dependence on the Zener-Hollomon parameter as material deformed via a conventional hot working process.