Creep-fatigue behaviour and life prediction

This thesis describes an investigation into the creep-fatigue behaviour and life prediction for high temperature materials. The methodology adapted in this research was not experimental, but, analytical using data compiled from several sources. High temperature low cycle fatigue (HTLCF) data generated internationally on 0.5Cr-Mo-V, ICr-Mo-V, 1.25Cr-Mo, 2.25Cr- IMo, 2.25Cr-lMo-V and 9Cr-lMo low alloy steels were compiled and analysed to identify trends in creep-fatigue behaviour and life prediction for those steels. Effects of alloying elements such as chromium and vanadium were investigated and it was shown that with increase in chromium content the life improved, but with vanadium addition to a 2.25Cr-Mo steel the life was lowered. For the annealed condition, in which the material tensile properties were nearly half the value for the normalized and tempered condition, the 2.25Cr-lMo steel had higher life.