Flaw detection in three-dimensional shape portion using uniform eddy current multiprobe

We designed exciting coils of uniform eddy current multiprobes with considering the shape of structures in order to obtain a uniform eddy current flow. A probe for a flat plate could obtain clear signals for an electrical discharge machining (EDM) slit of depth 0.5 mm and distinguish EDM slits arranged at 2 mm intervals. We confirmed that stress corrosion cracking (SCC) is detectable with sufficient sensitivity using the developed multiprobe. The probe for a curved portion obtained clear signals for the EDM slits on a curved surface of radius 25 mm. Moreover, we examined the technique for estimating crack shape from detection signals.