Verification of the prediction methods of strain range in notched specimens made of Mod.9Cr-1Mo

Ando, Masanori ; Hirose, Yuichi*; Date, Shingo*; Watanabe, Sota*; Enuma, Yasuhiro*; Kawasaki, Nobuchika 

To verify the strain prediction method of discontinues structures at evaluated temperature, low cycle fatigue tests were carried out with notched specimens made of Mod.9Cr-1Mo. Deformation control fatigue tests and thermal fatigue tests were performed by ordinary uni-axial push-pull test machine and equipments generating the thermal gradient in the notched plate by induction heating. Crack initiation and propagation process during the fatigue test were observed by the digital micro-scope and replica method. Then the ranges of several strain predictions and estimations were compared with the test results. Stress Reduction Locus (SRL) method, simple elastic follow-up method, Neuber's rule method and the methods supplied by elevated temperature design standards were applied. Through these results, the applicability and conservativeness of these strain prediction and estimation methods is discussed.