AbstractPrediction of the evolution of grain size in hot rolling of Al–5Mg alloy (AA 5056) is described in this paper. Published equations that relate microstructure to processing conditions in aluminium are incorporated into a thermomechanical model of hot rolling. Detailed modelling of the distribution of temperature, strain, and strain rate (Zener–Hollomon parameter) allows prediction of through thickness variation in the microstructure. The model described in this paper was developed to examine the effects of rolling process parameters (roll speed, reduction, strip entry temperature, and interpass time) on the extent of recrystallisation and grain size in the resulting microstructure.MST/1439