What is the primary purpose of using eddy current testing in non-destructive testing?

The primary purpose of using eddy current testing in non-destructive testing is to inspect for surface and sub-surface flaws. Eddy current testing utilizes the principles of electromagnetic induction to detect discontinuities that could affect the integrity and performance of a material. When an alternating current flows through a coil, it generates an electromagnetic field that induces eddy currents in conductive materials. If there are any flaws, such as cracks or inclusions, the flow of these eddy currents will be disrupted, leading to measurable changes in the coil's impedance.

This method is particularly effective for identifying defects close to the surface or just below it, making it a valuable technique in industries where the integrity of components is critical, such as aerospace, automotive, and manufacturing. The sensitivity of eddy current testing can be adjusted to detect various types of flaws, depending on the settings and the specific application.

While measuring the thickness of material, determining conductivity, and measuring temperature are relevant activities in material testing, they are not the primary focus of eddy current testing. In contrast, the ability to detect and characterize flaws is what makes eddy current testing a favored choice in non-destructive evaluation processes.