Corrosion Fatigue Crack Growth Behavior of 304L Stainless Steel in High Temperature and High Pressure Water

The fatigue crack growth rate of 304L SS was measured at 325℃ in air and oxygenous ultrapure water based on direct current potential drop (DCPD) method. Results were predicted and analyzed with FORD-ANDRESEN model, Bechtel Bettis model and PSI model. The fatigue fracture surface was observed by scanning electron microscopy (SEM). The results showed that the fatigue crack growth rate was accelerated as high as 1 000x at lower frequency & lower load; while only 1.5x at higher frequency & high load. FORD-ANDRESEN model was more proper and accurate for explaining the mechanism of corrosion fatigue and predicting the corrosion fatigue crack growth rate. Bechtel Bettis model and PSI model could estimate and compare the experimental results, but could give explanation of the effects of various parameters on crack growth. The fatigue fracture surfaces revealed obvious fatigue striations, and fatigue failure was transgranular attack.