Modelling of Microstructure Evolution during Thermoplastic Deformation of Steel by a Finite Element Method

A microstructure evolution model was coupled into finite element method to evaluate the dynamic recrystallization (DRX) and deformation behavior of low carbon steel under hot working. The flow stress curves and recrystallized grain size is measured from hot compression tests performed on Gleeble-1500. The recrystallization kinetics is expressed as Avrami equation calculated from measured flow stress curves including the effect of work hardening (WH), dynamic recovery (DRV)and DRX. Taking a hot compressed cylinder sample of Q235 as an example, an obvious non-uniform deformation is observed although the assumption of uniform deformation is commonly applied in this case. Microstructure evolution and macroscopic mechanical behavior of this sample were simulated and compared with measurements to examine the availability of the developed model.