Study on Fatigue Strength of 2Cr11Mo1NiWVNbN Steel for Turbine Blades

The fatigue strength of 2Cr11Mo1 NiWVNbN steel for turbine blades was measured by the staircase method, and the measurements was also calculated and verified through the empirical formulas, Basquin model and Langer model respectively.The results showed that the conditional fatigue limit of 2Cr11Mo1 NiWVNbN steel was 530 MPa at 100℃ which would be greater than that of 411 MPa calculated by the empirical formula. This was caused by dispersion strengthening of M₂₃C₆ precipitated phases and improved the hardenability of the test steel by Cr and Mo elements. The conditional fatigue limit of Langer model fitting was closer to measurements than that of Basquin model fitting, and the fatigue limit stress with different expected survivability fitted through Langer model had a smaller dispersion than that fitted through Basquin model. It was suggested that Langer model should be adopted to calculate the fatigue strength of 2Cr11Mo1 NiWVNbN steel.