SUS 304 鋼の長時間クリープ疲労試験結果に基づく寿命評価法の提案

概要

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Failure induced by creep-fatigue damage during operation, is a important failure mode to be avoided in high temperature structural components of thermal and nuclear power plants. Prediction of failure mechanism under creep-fatigue conditions in actual plants, and evaluation of the validity of creep-fatigue life prediction methods need to be done on the basis of long-term creep-fatigue test results. In this study, long-term creep-fatigue tests with up to 10 hours strain peak dwell were conducted using 304 stainless steel and the subsequent failure mechanism and creep-fatigue life prediction method were discussed. From the detailed observations of the failure speoimens using a scanning electron microscope, many creep cavities and microcracks at grain boundaries were observed inside specimens. It was indicated that the main crack initiated on the specimen surface and propagated favorably on the cavitated grain boundaries under long-term creep-fatigue conditions with a tension hold period of over 30 min. A creep-fatigue life evaluation method was proposed considering the interaction between fatigue and creep damage based on the failure observation. The experimental data of long-term creep-fatigue life in this study and existing literatures were compared with the predicted life by the proposed method and it showed good agreement.
社団法人日本材料学会の論文
1992-12-15