Eddy current testing techniques are commonly used for the non-destructive (NDT) examination.

Eddy current testing is used to detect surface and near surface defects of a large variety of metallic structures, including heat exchanger tubes, aircraft fuselage, and aircraft structural components. Without the need to remove surface paint from the item under test. Eddy current testing technique is used for the inspection of conductive materials without the need to remove non-conductive coatings. Its applications range from crack detection, material sorting, coating thickness measurement, weld testing and tube testing.

Eddy Current Testing

An alternating current is passed through a coil in order to create an alternating magnetic field which is used to induce a localised current (eddy current) into the material under test. Discontinuities such as fatigue cracks will interrupt the flow of eddy currents and alter the terminal impedance of the test coil. The amplitude and phase of the received signal can be interpreted to ascertain the severity and exact location of any discontinuities found.

Advantages

  • Able to detect defects of ≥ 0.5mm in length under favourable conditions.
  • The ability to detect defects through non-conductive surface coatings more than 5mm thickness.
  • Accurate conductivity measurements.