NON DISTRUCTIVE TESTING - HEAT TREATMENT - PLANT INSPECTION

ET - EDDY CURRENT

ET - Eddy Current

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

 

 

 

Pros

ET inspection is extremely versatile; the method can be applied to many inspection problems provided the physical requirements of the material are compatible with the inspection method.

 

Cons

Some variables in a material that are not important in terms of material or part serviceability may cause instrument signal that mask critical variables or are mistakenly interpreted to be caused by critical variables.

    Italsabi