Effect of Temperature on High-Cycle Fatigue Properties of 2CrMo Alloy Steel for Turbine Rotor

The tensile test and axial stress controlled high-cycle fatigue test were carried out on an imported 2CrMo alloy steel for turbine rotor at room temperature and high temperature (450, 500, 566℃). The high-cycle fatigue stress-life curves of the steel were obtained based on test data, and curved surface of median life was obtained by generalized curved surface of median model. The effect of temperature on the high-cycle fatigue properties was studied. The results show that yield strength, tensile strength and elastic modulus decreased with increasing temperature. High-cycle fatigue life decreased with increasing temperature at the same stress level. The influence of stress level on fatigue life was great at high stress ratio (0.5,0.8). The high-cycle fatigue fracture under low stress ratio (-1,-0.3) was a typical high-cycle fatigue fracture under axial load; the fatigue source was multi-source at high temperature and a single crack source at room temperature. At high stress ratio (0.5,0.8), high-cycle fatigue fracture presented tensile fracture characteristics; fracture had obvious radial zone, fiber zone and shear lip zone at room temperature, and had only fiber zone and shear lip zone at high temperature.