A new eddy current sensor composed of three circumferential gradient winding coils

This paper proposes a new eddy current testing sensor composed of three planar fan-shaped circumferential gradient winding spiral coils. We study the crack detection principle by using the ECT sensor. The experiment of crack detection is set up and a series of samples machined with a slot at different size are detected by using the ECT sensor. Finally the quantitative estimations of crack width, depth and extension direction are studied, which prove the method is feasible and reliable.