Comparison of creep-fatigue evaluation methods with notched specimens made of Mod.9Cr-1Mo steel

Ando, Masanori ; Hirose, Yuichi*; Karato, Takanori*; Watanabe, Sota*; Inoue, Osamu*; Kawasaki, Nobuchika ; Enuma, Yasuhiro*

To compare and evaluate these estimation methods, a series of creep-fatigue test was carried out with notched specimens. All the specimens were made of Mod.9Cr-1Mo steel. Deformation controlled creep-fatigue tests and temperature controlled creep-fatigue tests were performed and creep-fatigue lives, crack initiation and propagation processes were observed by digital micro-scope and replica method. A series of elastic Finite Element Analysis were carried out and number of cycles to failure was predicted by several creep-fatigue damage evaluation methods. Then these results were compared with test results. Four types of evaluation methods which are stress reduction locus method, simple elastic-follow up method, the method using conventional Neuber's rule and the methods described in JSME FBR design code were applied. In addition that, experimental based estimation were also compared.