Eddy Current Testing
Eddy current testing is a nondestructive testing (NDT) method used for a variety of purposes, such as detecting surface and subsurface flaws, locating cracks in bolt holes, taking material and coating thickness measurements, identifying materials, and establishing the heat treatment condition of certain materials.
Eddy currents are swirls of electric currents induced within electrically conductive materials by a changing magnetic field within the conductor. Variations in the phase and magnitude of the current flow cause changes in the phase and amplitude of the measured signal, which are displayed on an eddy current flaw detector screen.
Eddy current inspection finds use in numerous industries, including aviation and aerospace.