Low-cycle fatigue life estimation of steam turbine rotor steels at high temperature

Nine methods currently available for estimation of fatigue properties from simple tensile data are discussed in detail. The estimation accuracies of these methods were compared according to the test data of nine types of steam turbine rotor steels. The results showed that the values calculated using the nine methods resulted in unacceptable values. In double logarithmic coordinates, the nine method functions were linearly modified, where the predicted lives were all less than quadruple the observed lives, except for the mixed method. A new method that takes the temperature influence into account is presented, which is suitable for fatigue life estimation of steam turbine rotor steels at high temperature (400 degrees C-600 degrees C). The estimation results show that the new method can provide acceptable accuracy.