The paper proposes a new method for determining critical damage values in hot forming processes. The method first involves performing tensile tests of axisymmetric samples and then simulating these tests numerically. Simulations are performed by the finite element method in a three-dimensional state of strain, including thermal phenomena occurring in the forming zone. The elaborated method is universal and can be used for different materials. The study is performed for two steel grades, i.e., R200 railway steel and 100Cr6 bearing steel. The results demonstrate that critical damage values strongly depend on the forming temperature.
Keywords: FEM; damage criterion; hot forming of steel; tensile test.