The fatigue-crack growth and fracture characteristics of a precipitation-hardened semiaustenitic stainless steel

Fatigue-crack propagation and residual static-strength data on PH15-7Mo (TH 1050) stainless steel are presented in this thesis. In addition, the capability of McEvily and Illg's crack-growth analysis and Kuhn and Figge's residual strength analysis to correlate the test data has been investigated. Axial-load fatigue-crack propagation (at R = 0 and -1) and residual static-strength tests were conducted, on 2-inch-wide sheet specimens made of PH15-7Mo (TH 1050) stainless steel. Analysis of the data showed that as individual analysis methods both analyses satisfactorily correlated the majority of the test data. However, the material constants derived in the two analyses differed significantly. This difference was attributed to the different amounts of work-hardening which occurs in the material prior to failure in the two cases.

The effects of the different stress ratios on fatigue-crack growth were studied. In addition, the capability of the residual-strength analysis to predict the effects of changing buckling restraint in the vicinity of the crack.and of changing specimen width were investigated.