What occurs when parts to be penetrant tested are at a low temperature?

When parts to be penetrant tested are at a low temperature, the penetrant may become viscous. Low temperatures can significantly affect the physical properties of penetrants, which are typically designed to flow into surface discontinuities. As the temperature drops, the viscosity of the penetrant increases, making it thicker and less fluid. This reduced fluidity can hinder the penetrant's ability to effectively enter small cracks or defects in the material being tested, potentially leading to inadequate testing results.

In contrast, while other effects could occur at low temperatures, they do not specifically encapsulate the primary concern about the behavior of penetrants during testing. For instance, while low temperatures can lead to a slower evaporation rate or reduced adhesion, these issues are secondary to the primary concern of viscosity and fluidity, which directly impacts the efficiency of the test. Therefore, understanding the impact of temperature on the viscosity of the penetrant is essential for ensuring accurate and effective non-destructive testing procedures.