Prediction of Corrosion Fatigue Life

Abstract

It can be regarded that the corrosion fatigue life consists of three processes; the growth of corrosion pits, the initiation of fatigue cracks from these pits and the propagation of fatigue cracks. Especially, the fatigue crack propagation life for a member subjected to considerably fast stress repetition, such as a turbine blade, is considered to be extremely short and sometimes neglected compared to other lives. The corrosion fatigue life in such a case may be estimated by predicting the corrosion pit growth behavior and the critical pit depth of fatigue crack, initiation with a help of the fracture mechanics technique.
It is made clear in this paper that the life predicted, regarding the corrosion pit as a microcrack, is in good agreement with the empirical results as well as that predicted by means of the conventional method proposed by the authors.