Why is Eddy current testing conducted at various frequencies?

Eddy current testing (ECT) involves the utilization of alternating current to induce eddy currents in conductive materials, which interact with the material's properties and any existing defects. Conducting ECT at various frequencies allows for the differentiation between types of defects and enhances material characterization.

Different frequency levels affect the depth of penetration of eddy currents within the material and, as a result, the sensitivity to specific types of defects. High frequencies tend to induce currents that are more sensitive to surface defects, while lower frequencies can penetrate deeper and may be better suited for detecting subsurface flaws. This adaptability makes it possible to tailor the testing approach based on the material being examined and the types of discontinuities that are of interest.

By using a range of frequencies, inspectors can gain a more comprehensive understanding of the material’s condition and any potential issues, leading to improved accuracy and effectiveness in assessments. This capability is crucial for ensuring the integrity and safety of engineered components across various applications.