What role does grain size play in eddy current testing results?

Grain size significantly influences electrical conductivity, which in turn affects eddy current testing results. In materials, the size and arrangement of grains can alter the movement of charge carriers within the metal. With finer grains, there might be more grain boundaries that can scatter electrons, leading to variations in conductivity. This change can directly impact the eddy current's ability to penetrate the material and the way it flows through it.

Eddy current testing relies on changes in the electromagnetic field in response to the material properties. When grain size alters the electrical conductivity, it can subsequently impact the eddy current's amplitude and phase, which are critical for interpreting test results. Thus, understanding the grain size is essential for assessing the material's quality and characteristics through eddy current testing.