On the origin of equiaxed austenite grains that result from the hot rolling of steel

An investigation has been conducted into the influence of hot rolling on the microstructure of austenite in both a low alloy (transformable) and an austenitic stainless steel. Specimens of each steel were reheated and then given a single 50 pct reduction at various temperatures, after which the specimens were water quenched. The specimens were analyzed using optical, transmission electron and X-ray metallography. The results of these experiments showed that both steels exhibited equiaxed grains after high temperature rolling, elongated grains after low temperature rolling and a mixture of both types of grains after rolling at intermediate temperatures. One of the principal goals of this work was to study the origin of the equiaxed grains that result from high temperature rolling. Information obtained from dislocation observations and texture analysis has led to the conclusion that the mechanism most likely responsible for the equiaxed grains in as-rolled austenite is dynamic recrystallization. Formerly a Graduate Student, University of Pittsburgh