Extrusion applications require a strict control of the mechanical proprieties of the extrudates, in particular when undergoing severe loading conditions like in the transportation sector. Profile mechanical properties directly depend on its microstructure and texture, which are the result of multiple mechanisms based on precipitation mechanism or on grain shape evolution (grain refinement, recrystallizations, recovery and grain growth). In this direction, predicting the final profile microstructure under specific process parameters in the die design stage is of great relevance. The present study involved experimental activity on grain size measurements of profile and butt during interrupted direct extrusion of an AA6082 round profile. The grain size measurements were coupled with simulation results in order to regress analytical models based on effective strain, strain rate and temperature. Finally, the developed model was implemented in the numerical code by means of a subroutine that can be used as microstructure prediction tool.