Penetrant Testing

Penetrant Testing (PT) is a method that uses the capillary action principle to make
open-to-surface defects easier to identify.

Dye or fluorescent penetrant gets applied to a clean surface and is allowed to penetrate for some time, called ‘dwell time.’ Dwell time allows the fluid a chance to be drawn into voids, cracks, or pores, and then the excess is rinsed off, then the material is allowed to dry, followed by the application of a dry powder or wet-aqueous
developer. The developer draws out the penetrant that has filled the voids and cracks and creates a contrasting appearance that reveals the imperfections to the inspector.