オーステナイト系ステンレス鋼の応力腐食割れ感受性に関する微視的組織の電磁非破壊評価

Evaluation of microstructure related to susceptibility to stress corrosion cracking in austenitic stainless steels based on electromagnetic nondestructive evaluation

内一 哲哉*; 及川 諒太*; 高木 敏行*; 浦山 良一*; 根本 義之  ; 高屋 茂  ; 欅田 理*

Uchimoto, Tetsuya*; Oikawa, Ryota*; Takagi, Toshiyuki*; Urayama, Ryoichi*; Nemoto, Yoshiyuki; Takaya, Shigeru; Keyakida, Satoshi*

This paper discusses the feasibility of nondestructive evaluation of micro-structure related to susceptibility to stress corrosion cracking in austenitic stainless steels. For the purpose, tensile tests at elevated temperatures were conducted using model alloys simulating radiation-induced segregation (RIS), and magnetization curves of the tensile test specimens were measured by vibrating sample magnetometer (VSM). Microstructure of magnetization of the tensile test specimens was observed by magnetic force microscopy (MFM). The mechanism of magnetization change was discussed through these observations. Finally, non-linear eddy current method was carried out for the tensile test specimens. It is shown that the 3rd higher harmonic ratio of the pick-up signal is related to the targeted nominal strain.