Finite element analysis of hot forging with flow softening by dynamic recrystallization

The change of flow stress due to dynamic recrystallization (DRX) during hot forming process is investigated. A series of mechanical tests had been conducted at various temperatures, and constitutive relations and recrystallization kinetics were formulated from the test results. The effect of DRX on the flow stress was implemented in a commercial FEM code by conditioned remeshing followed by remapping of the state variables. The datum strain of stress compensation was optimized to minimize the overestimation of forming loads. Suggested datum strain were formulated as an exclusive function of critical strain for recrystallization and validated by mechanical tests.