Eddy Current Testing

Eddy current testing for Cracks and Flow

Eddy Current testing for cracks and flow

Eddy current is one of the many non-destructive treatment methods that practices the principle of electromagnetism as a root to conduct the examinations. There are numerous other methods like Remote Field Testing, Flux Leakage, and Barkhausan noise who also uses the principle of electromagnetism. Electromagnetic induction is the process that generates an eddy current. When a conductor like the copper wire is treated with the alternating current, a magnetic field is formed in and around the conductor. If you bring another electrical conductor into the close proximity of this changing magnetic field, current will be induced in this second conductor. Eddy currents are the induced currents that flow in a circular path. The name eddy current comes from “eddies” that are formed when liquid and gas flow in a circular path around the hurdles when the conditions are right.

One of the biggest advantages of the eddy current as an NDT tool is the variety of inspections and measurements that can be performed. Eddy Current can be used for the following:

  • Crack Detection
  • Material thickness measurements
  • Coating Thickness Measurements.

Eddy current inspection also delivers numerous advantages like the following:

  • Sensitive to small cracks and other defects
  • Detects the defects on the surface and near it
  • The inspection provides immediate results
  • Minimum part preparation is required
  • Examines complete shape and size of conductive materials

Eddy current testing is used on a large scale to detect the cracks and flows on the surface and the also the near surface. One of the best systems to find the defects in the metallic components is Criterion NDT Eddy Current test systems. The testing is extremely fast, accurate, repeatable and the technology is well-suited for the in-line production inspection against the magnetic particle and dye penetrant testing.

Our systems are smoothly incorporated into the manufacturing production lines where ultimately they provide checks and balances for production processes. To detect the crack and the flow eddy current test is performed and is accomplished by running energized coils over an area that is to be tested. The eddy current is forced to deviate as soon as it passes over the crack of flow, and this deviation is detected by the eddy current instrument. Alarm limits are adjusted in a way that the instrumentation triggers only on flaws that are serious and critical. Eddy current crack and flow testing can be performed at the rate of 100 parts per minute, this may vary depending on the application, making the testing simple to incorporate into a production line. Some of the other advantages of the eddy current crack and flaw inspection are:

  • Instantaneous responses
  • Extreme sensitivity to the surface flaws
  • Green technology requiring no chemicals
  • Reliable Reproducible results
  • Easy integration into production lines via industrial I/O for 100% part inspection


The dynamic eddy current testing saves the parts from the greater damage and also increases the durability of the products. The testing process is very much in the practice and has proved very efficient for various industries.

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