In magnetic particle testing, what could lead to difficulties in interpretation of results?

Smearing of metal across discontinuities can lead to significant difficulties in interpreting results during magnetic particle testing. When metal is smeared over the area of interest, it can obscure the actual discontinuities that need to be detected. This smearing can create false indications or mask real defects, leading to incorrect conclusions about the integrity of the part being tested. It makes it challenging for the inspector to discern whether a visible indication is a result of a legitimate flaw or simply debris from the smearing action. Therefore, maintaining a clean testing surface and ensuring that the area is free of contaminants is crucial for accurate interpretation of indications.

While other factors like excessive moisture in the testing area or low levels of magnetization can affect the effectiveness of the testing process, they do not directly obscure the actual indications in the way smearing does. High visibility of colors generally aids in interpretation rather than hindering it.