What happens if the surface temperature of the test part is excessively hot?

When the surface temperature of the test part is excessively hot, it can lead to a loss of fluorescent brightness in the penetrant. This occurs because high temperatures can increase the rate of evaporation of the carrier solvent in the penetrant, which can diminish the ability of the penetrant to remain effective. The fluorescent dyes used in liquid penetrants rely on specific chemical properties to fluoresce optimally under UV light, and excessive heat can degrade these properties, resulting in reduced visibility during inspection.

Maintaining an appropriate temperature during testing is critical to ensure that the penetrant can perform its intended function of revealing surface defects effectively. In contrast, while it may seem intuitive that heat could enhance a penetrant's effectiveness, it actually has the potential to compromise its performance and the reliability of the inspection results.