Influence of thermal aging and notch on low cycle fatigue strength of forged mod. 9Cr 1Mo steel at elevated temperature
Nishino Seiichi; Shiozawa Kazuaki; Kojima Akihiro; Seo Shoitsu; Yamamoto Yuichi
Abstract:In this study, the influence of thermal aging and notch on low cycle fatigue strength of forged mod. 9Cr 1Mo steel was investigated at elevated temperature. Total strain controlled low cycle fatigue tests using the smooth specimen and load controlled low cycle fatigue tests using the notched specimen were carried out at 873 K in air. The triangular, tension hold and compression hold trapezoidal waveforms were applied to the specimens in a series of the tests. From the experimental results, there is no effect of the thermal aging on strain controlled low cycle fatigue life using the smooth specimen with each strain waveform. However, low cycle fatigue life of the notched specimen decreased by thermal aging under load controlled condition with triangular and tension hold trapezoidal waveform. Key Words:low-cycle fatigue, Mod.9Cr-1Mo steel, elevated temperature, thermal aging, notch effect