Lifetime Prediction of Steam Turbine Components under Multiaxial Thermo-mechanical Fatigue Loading

摘要

Lifetime prediction of steam turbine components under biaxial thermo-mechanical fatigue (TMF) loading of modern high chromium steel is prerequisite for design optimization. In this paper a phenomenological method which envelopes the synthesis of stress strain hysteresis loops and damage assessment under considering creep fatigue interaction is extended to multiaxial loadings. It is proposed as a post processing step depending on the results of a preceding finite element analysis based on a constitutive material model. Recalculation of biaxial service-type experiments on cruciform specimen of modern high chromium rotor steel 10CrMoWVNbN shows satisfactory results for lifetime estimation.