Eddy Current Testing

Eddy current testing uses the electromagnetic induction of electrical currents – eddy currents – in a material. The electrical currents are affected by any section change in the material, e.g. the presence of defects. These current changes are detected by the test instrument, often by the use of a probe which induced the currents initially, they are then displayed on a meter or a phase analysis screen which traces the movement by the use of a flying dot.

Eddy current testing is quite versatile. It is used for coating thickness measurements, cladding thickness measurements and alloy sorting as well as flaw detection.

Eddy current testing is able to detect sub-surface discontinuities, but the depth of eddy current penetration is limited. It is excellent for surface flaw detection, but for all types of testing, can only be used on conductive materials; both magnetic and non-magnetic.

Many different types of probe attachments are available, these include: internal bobbin-type coils, external coils, knife edge probes and many unique designs for specific applications.