High-temperature creep-fatigue-oxidation behaviors of P92 steel: Evaluation of life prediction models

Damages caused by the effects of cyclic loading (fatigue) and high temperature (creep and oxidation) have been considered critical and need to be appropriately evaluated. A series of strain-controlled fatigue and creep-fatigue tests are performed on P92 at 873 K under oxygen-containing environment. The creep-fatigue life prediction results are summarized using models based on strain-range partition, Manson-Coffin equation and linear damage summation (LDS) rule. Obviously, the models based on the LDS rule show relatively good performance with an error band of +/- 2.5. In view of the adverse effects of oxidation on creep-fatigue endurance, this paper further develops a physically-based oxidation damage equation, which is incorporated into LDS rule for the improvement of life assessment. The predicted and experimental results falling into +/- 1.5 error band proved the accuracy of the proposed oxidation damage equation in the LDS rule. Additionally, model selection criteria are recommended to evaluate the model prediction capabilities.