In the present study, the variation of the critical ductile damage during hot deformation was investigated using hot compression testing and finite element simulation. Based on the obtained results, the critical ductile damage diagram was developed for AISI 321 austenitic stainless steel. Results showed that the value of critical damage is not constant during deformation in the temperature range of 800–1200 ∘C. It is also concluded that the critical ductile damage value is varied between 0.24 and 0.41 depending on hot deformation conditions. This means that, the critical ductile damage value is increased with increasing deformation temperature and decreased by increasing strain rate.
