Low-cycle fatigue behavior of AISI 347 stainless steel in salt water

The aim of this study is to investigate the influence of strain ratio, frequency, and waveform on low cycle fatigue (LCF) behavior of AISI 347 stainless steel in air and NaCl solution. Results showed that at high strain amplitude region the fatigue lives in both environments were comparable, implying a lack of environmental effect due to insufficient amount of local dissolution. However, at low strain amplitude region, a corrosive effect did exist and the fatigue lives in NaCl solution were decreased with an increase in strain ratio to a greater extent, as compared to those in air. This might be attributed to a tensile-mean-stress effect and its interaction with an enhanced, localized corrosive reaction. The degree of influence of the aggressive salt water on the LCF life was not increased as the loading frequency was reduced or a hold time was added at the tensile peak strain. The LCF life data in the given environments at various strain ratios could be well correlated by a modified SWT model as well as a modified Manson-Halford model.