Prediction of Survice Life of Boiler Supperheater Tubes under Hot Corrosion and Creep Environment

Abstract

In order to predict the survice life of boiler supperheater tubes under high temperature corrosion and creep conditions, two models for describing the damage accumulation with crack and without crack respectively were costructed. Life time was calculated numerically for combinations of various corrosion conditions and creep conditions. Basing on the models proposed here, many situations notionally assumed were analysed. Results obtained suggested that the improvement of corrosion resistance was the most effective countermeasure for survice life improvement. Material degradation in creep resistance shorten a survice life although the strengthing in creep resistance does not effectively prolong the survice life. Finally, a possibility that synergestic reaction of corrosion and creep may considerably reduce the survice life is suggested from the creep test result performed under corrosive environment.