Kinetics of recrystallization and grain growth of cold rolled TWIP steel

Hot rolled, laboratory-cast, TWIP steel samples (5.4 mm thick) of 22% Mn - 0.6% C (in mass-%) were cold rolled to different reductions (from 40 % to 70 %) and subsequently isothermally annealed for various times at temperatures ranging from 450 degrees C to 1100 degrees C. The evolution of recrystallization and grain growth was followed by control of the softening kinetics complemented by metallographic, OIM and microtexture observations. A map of the recovery, recrystallization and grain growth in the temperature-time space was obtained. In all instances, the grain size at the end of recrystallization was very fine, D <= 2 mu m and larger grain sizes were the result of grain growth. A range of grain sizes 2 mu m <= D <= 50 mu m was covered by the grain growth experiments. A phenomenological grain growth equation that is useful for the annealing control of this steel was derived from the measurements.