Eddy Current Inspection (ET) is based on the principles of electromagnetic induction and is used to identify or differentiate among a wide variety of physical, structural, and metallurgical conditions in electrically conductive ferromagnetic and nonferromagnetic metals and metal parts.
Eddy current inspection can be used to:
- Measure or identify such conditions and properties as electrical conductivity, magnetic permeability, grain size, heat treatment condition, hardness, and physical dimensions
- Detect seams, laps, cracks, voids, and inclusions.
- Sort dissimilar metals and detect differences in their compositions, microstructure, and other properties.
- Measure thickness of a nonconductive coating on a conductive metal, or the thickness of a nonmagnetic metal coating on a magnetic metal
- Uniform thinning
- Localized defects
- Measurement of residual thickness
- Measurement of the penetration of the defect
