Abstract
This study discusses the electromagnetic modeling of fatigue cracks in plant environment to improve accuracy of depth sizing with eddy current testing. For the purpose, the factors that influence eddy current signals of fatigue cracks are evaluated. Here, martensitic layer and oxide fillings in fatigue cracks are focused on as influencing factors, and oxides are systematically filled in fatigue cracks by thermal treatment. The measured EC signals change depending on the presence and type of filling oxides. Numerical simulations are conducted to discuss the electromagnetic modeling of cracks with oxide fillings. The types of oxides in the cracks are identified by Raman spectroscopy, and the martensitic layers in vicinity of crack faces are observed by magnetic force microscopy. These results support for the electromagnetic model of environmental fatigue cracks developed in this study.