Evaluation of creep damage in mod. 9Cr-1Mo steels by non-linear eddy current testing

Matsumoto, Takanori*; Uchimoto, Tetsuya*; Takagi, Toshiyuki*; Takaya, Shigeru  

Mod. 9Cr-1Mo steel is used in advanced fossil power plants. It becomes more important to manage creep damage because temperature and pressure in operating conditions become higher. In this study, it is an objective to evaluate microstructure change due to creep damage by nonlinear eddy current testing. Firstly, relationship between signal of nonlinear eddy current testing and microstructure of creep test samples of mod. 9Cr-1Mo steel was investigated. Next, nonlinear electro-magnetic analysis was performed by using FEM, and then models describe the relation between microstructure and magnetic property was discussed. As result, the possibility of quantitative evaluation of microstructure change due to creep damage by the proposed method is shown.