The Dye Penetrant Tests are aimed at identifying any superficial defects, such as discontinuities, cracks and missed fusions.
After carrying out the preliminary cleaning and preparation operations, liquids, solutions containing strong dyes or fluorescents are applied to the surfaces of the component to be examined.
By capillarity these liquids penetrate progressively into surface discontinuities. Once the excess liquid has been removed from the surface, a powder or a liquid detector is applied, whose function is to make visible the penetrant that has reached the discontinuities. In the case of fluorescent liquids, these are highlighted by subjecting the component to ultraviolet light.