What is eddy current testing in NDT?

 

What is an Eddy Current?

Eddy currents are currents that circulate in conductors like swirling eddies (a whirlpool) in a stream. They are induced by changing magnetic fields and flow in closed loops, perpendicular to the plane of the magnetic field.

eddy current test

How is Eddy current used in Non-Destructive Testing?

  • It is one of the electromagnetic methods of non-destructive testing.
  • It is used for identifying surface and subsurface defects in conducting materials.

Principle of Eddy Current Testing:

Electromagnetic Induction is the basic principle of ECT.

How is Eddy Current used for identifying a defect?

When eddy current is induced to an object/material which is being tested, by varying the electromagnetic field alternatively, there will be a change in pattern of the current flow when a defect is present in an object.

 

Eddy Current Testing

eddy current testing

 

Properties of Eddy Currents:

  • They are induced in closed loops.
  • They normally travel parallel to the coils windings.
  • Its density decreases with depth.

Different types of Eddy Current Probes:

Based on the method of operation:
  • Absolute probes
  • Differential probes
  • Reflection probes
  • Hybrid probes
Based on Application: Few examples:
  • Surface probes
  • Rotating Scanner probes
  • Manual bolt hole probes
  • Bobbin probes
  • Weld probes
Advantages of Eddy Current Testing:
  • Surface and subsurface defects can be found.
  • No physical contact is required.
  • Immediate test results.
  • Complex geometry can be inspected.
Applications of Eddy Current Testing:
  • Aerospace Industries
  • Railways
  • Marine Industries
  • Manufacturing Industries
  • Corrosion Detection in aerospace industries, steel tubings.

To know more about Eddy Current Testing and its application; please feel free to visit our website https://aqcinspection.com/ Advanced Quality Centre, Coimbatore, NDT Training Institute for NDT Courses and Certification https://aqcinspection.com/training/

Visit our technical and career updates at our Blog site https://advancedqualitycentre.blogspot.com . https://ndtcenter.blogspot.com; and our website https://aqcinspection.com/news-events/  for many more blogs.

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