Which three specimen parameters significantly influence eddy current testing?

In Eddy Current Testing (ET), the three specimen parameters that significantly influence the testing results are electrical conductivity, permeability, and material geometry.

Electrical conductivity is crucial because it determines how readily the material allows the flow of eddy currents. A material with higher conductivity will generate stronger eddy currents, which in turn affects the test results and the ability to detect flaws.

Permeability influences how magnetic fields interact with the material. It plays a role in how the eddy currents are induced, especially in ferromagnetic materials. The permeability can affect the depth of penetration of the currents and their distribution across the surface of the specimen, thus impacting the detectability of discontinuities.

Material geometry, including the shape and thickness of the specimen, affects the distribution of the eddy currents. Different geometries can lead to variations in how eddy currents flow, thereby influencing the testing response. Irregular shapes or variations in thickness might cause changes in the impedance, which is critical for accurately interpreting the test results.

These three parameters collectively determine the behavior of eddy currents and the effectiveness of the testing, making them vital for accurate evaluation during ET.