Modeling and Design Optimization of an Eddy Current Sensor for Superficial and Subsuperficial Crack Detection in Inconel Claddings

Inconel 625 alloys are currently being extensively used as a cladding material for carbon steel pipes. A common fabrication process for this is weld overlay, which can produce defects such as cracks, porosity, inclusions, and lack of fusion. Inspection of the cladded layers is, therefore, important for quality control and structural integrity evaluations. In this paper, finite-element models were used as a tool for eddy current sensor design to optimize their geometry and operating frequency for detection of common, expected defects in these layers. The sensor with the most interesting geometry was then built and tested to validate the results of the model. A good agreement was found between simulated and experimental results, showing that this is a robust strategy for special sensor design.