What may happen to the penetrant if a part is heated to a high temperature before testing?

When a part is heated to a high temperature before testing with penetrant, the penetrant may "flash" or evaporate rapidly. This phenomenon occurs because many penetrants are designed to be low-viscosity liquids that can penetrate small cracks and voids in a material. However, when exposed to high temperatures, the volatile components within the penetrant can evaporate, reducing its effectiveness and potentially leading to a failure to adequately reveal defects.

The rapid evaporation can hinder the penetrant's ability to wet the surface of the material, resulting in a loss of sensitivity during the inspection process. Therefore, it is crucial to adhere to recommended temperature guidelines for penetrant testing to ensure that the material maintains its optimal properties for detection of flaws.