Eddy Current

Eddy Current Testing (ECT) is a non-destructive testing (NDT) method that provides a fast efficient solution to detect near-surface anomalies, such as crack detection, in conductive material. Often, defects sit just below the surface of the inspection material or paint and other coatings applied to outer surface cover the anomalies.

ECT is based on the physics phenomenon of electromagnetic induction. In an eddy current probe, alternating currents flow through a wire coil and generate an oscillating magnetic field. The magnetic field from the coil is induced into the component to be inspected and any anomalies in the material create changes to the “eddy currents” or phase and amplitude of the measured signal which are displayed on an eddy current flaw detector as a distinct change in signal.

Eddy current inspection can be used in conjunction with other inspection methods for specific applications, such as ultrasonic and eddy current techniques used simultaneously for volumetric and surface inspections.

Advantages of Eddy Current Inspection Method

Faster scanning speed than conventional ultrasonic testing (UT)
Crack detection on or near the inspection surface
Requires no fluid couplant (unlike conventional UT)
Inspection surfaces need minimal preparation
Eddy current probes do not have to be in contact with the inspection surface
Eddy current signals penetrate through paint and coatings to provide results
Complex geometries can be investigated
Provides instant results with imaging systems