What does a Phase vs Amplitude plot help to visualize in Eddy Current Testing?

A Phase vs Amplitude plot is a crucial tool in Eddy Current Testing because it allows the technician to identify defects based on their unique characteristics. In the context of ET, the phase angle represents the shift between the magnetic field and the induced current generated by the testing coil. When a defect is present in the material, it alters the flow of eddy currents, causing a change in both amplitude and phase of the signal received.

By plotting these two parameters, the technician can visualize the relationship between them, which helps to differentiate between various types of flaws, such as cracks, corrosion, or inclusions, due to their distinct signatures. Each type of defect will exhibit a unique response in the plot, making it a valuable diagnostic tool for evaluating the integrity of materials. This visualization effectively assists in making accurate interpretations about the nature and severity of the defects detected during the testing.