Why are defects often challenging to classify in Eddy Current Testing?

The classification of defects in Eddy Current Testing can be influenced by the nature of the testing process itself. In multi-frequency testing, the use of various frequencies allows technicians to gather more detailed information about the material being tested and the defects present. Different frequencies can interact differently with defects depending on their type and size, which results in varying impedance changes. This characteristic enables technicians to distinguish between different types of defects, such as cracks, pitting, or corrosion, thus aiding in accurate classification.

By employing multi-frequency testing, the sensitivity can be increased for specific defect types, allowing for a more comprehensive analysis and a better understanding of the material's integrity. This approach is particularly beneficial when it comes to complex materials where defects may not be easily identifiable at a single frequency. Through analysis of impedance at multiple frequencies, technicians can more effectively classify defects based on their distinct responses, making it a valuable technique in the field of Eddy Current Testing.