The forming process of hot rolling not only has obvious commercial importance but also is scientifically challenging to understand. Accurate characterization is difficult as material physics affecting plastic deformation change on the same time scale as that of the process itself. Recovery and recrystallization provide examples: the development of an annealed state may occur between rolling passes, with subsequent impact on upcoming rolling passes. We have used the constitutive response of the metal in interrupted loading experiments to ascertain whether recrystallization or recovery is an active mechanism as a function of deformation history, complimenting a study of Wells, et. al (1998).