Evaluation of long term creep-fatigue life of stainless steel weldment based on a microstructure degradation model
Asayama Tai; Hasebe Shinichi
Abstract:This paper describes a newly developed analytical method of evaluation of creep-fatigue strength of stainless weld metals. Based on the observation that creep-fatigue crack initiates adjacent to the interface of sigma phase/delta-ferrite and matrix, a mechanistic model which allows the evaluation of micro stress/strain concentration adjacent to the interface was developed. Fatigue and creep damage were evaluated using the model which describes the microstructure after exposed to high temperatures for a long time. Thus it was made possible to predict analytically the long-term creep-fatigue life of stainless steel metals whose microstructure is degraded as a result of high temperature service. Key Words:stainless steel weld metal, degradation of microstructure, creep-fatigue