What is Eddy Current Inspection?

Eddy current testing (ECT) is a non-destructive testing (NDT) method used to detect surface and near-surface flaws in conductive materials. It works by inducing eddy currents (circulating electrical currents) within the test object using an alternating current-carrying coil. These eddy currents generate a secondary magnetic field that opposes the primary field. Flaws or changes in material properties disrupt the flow of eddy currents, altering the impedance of the coil. By measuring these changes in impedance, the presence, size, and location of flaws can be determined. It is commonly used for crack detection, material sorting, coating thickness measurement, and heat treatment verification.