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. 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 Properties of Eddy Currents: They are induced in closed loops. They normally travel parallel to the coils windings. ...