Development of generic creep–fatigue life prediction models

This paper presents a data bank that was compiled from published and unpublished sources. Using these data, low cycle fatigue curves were generated under a range of test conditions showing the effect of test parameters on the Coffin–Manson behavior of steel alloys. Phenomenological methods of creep–fatigue life prediction are summarized in a table showing number of material parameters required by each method and type of tests needed to generate such parameters. Applicability of viscosity method was assessed with creep–fatigue data on 1Cr–Mo–V, 2.25Cr–Mo and 9Cr–1Mo steels. Generic equations have been developed in this paper to predict the creep–fatigue life of high temperature materials. Several new multivariate equations were developed to predict the creep–fatigue life of following alloy groups; (1) Cr–Mo steels, (2) stainless steels and (3) generic materials involving the materials from the following alloy groups, solder, copper, steels, titanium, tantalum and nickel-based alloys. Statistical analyses were performed in terms of coefficient of correlation (R2) and normal distribution plots and recommended these methods in the design of components operating at high temperatures.