Computational modelling of static recrystallization and two dimensional microstructure evolution during hot strip rolling of advanced high strength steel

A coupled Monte Carlo simulation technique has been developed for hot rolling of advanced high strength steel (AHSS) to simulate the microstructure evolution during static recrystallization. The physically based dislocation evolution model has been formulated to study the deformation behaviour of austenite during hot rolling. The model envisages both hardening and softening regimes during deformation. The evolution of dislocation density as a function of strain has been predicted and the deformation stored energy has been calculated. The computed value of the stored energy of the system has been passed to the Monte Carlo model to construct the total energy Hamiltonian of the lattice system. Both the models have been seamlessly coupled to simulate the kinetics of recrystallization, recrystallized grain size and evolution of microstructure at different strains during forming. A continuum microstructure is mapped onto a two dimensional square lattice and high fidelity simulation has been carried out to characterize recrystallization behaviour. The Avrami exponent obtained from the kinetics of recrystallization predicted by coupled Monte Carlo model has been validated with the published literature. The recrystallized grain size and evolution of microstructure predicted by the coupled Monte Carlo model has been verified with the published data for a typical AHSS and found to be in very good agreement.