What is the primary purpose of testing with an encircling coil in eddy current testing?

The primary purpose of testing with an encircling coil in eddy current testing is to improve the sensitivity and uniformity of the test. An encircling coil configuration allows for a more consistent interaction with the material being tested, leading to better detection of flaws, such as cracks or other discontinuities within the test specimen. This type of arrangement ensures that the eddy currents are induced uniformly around the surface of the material, which helps in accurately assessing the integrity of the component. Enhanced sensitivity means smaller defects can be detected, while uniformity contributes to reliable and repeatable measurement results.

Utilizing an encircling coil is particularly advantageous in scenarios where the geometry of the test specimen might otherwise lead to inconsistent eddy current responses. Thus, achieving a high level of sensitivity and consistent readings is crucial in non-destructive testing applications, making this approach essential for effective eddy current testing.