Sensitivity effect of elastic modulus on combined stress of hot forging die

Stresses, including thermal, mechanical and combined stress, are the root causes leading to hot forging die failure. Stress amplitude is affected by the material properties, such as elastic modulus. In order to select die material for improving die service life, a 2D FE model of cake shaped workpiece is developed to analyze thermal, mechanical and combined stress of hot forging die with different level elastic modulus. Three kinds of stress distribution are explored. The results show that thermal stress is about 10 times than mechanical stress at the die cavity surface which is the easiest failure location, and approximate linear relationship exists between stress, including thermal and combined stress, and elastic modulus. Die material with large room temperature and temperature-sensitive elastic modulus should be selected.