Penetrant testing: definition and principle
Penetrant Testing

Penetrant testing (symbol PT) is a NDT method which is the logical extension of visual testing (symbol VT).

This method can be used to highlight open-to-surface discontinuities on the surface of metallic materials and certain non-metallic, essentially non-absorbent materials.

Penetrant testing is an all-round method, as it can be used to inspect a part in a single operation, or to process a large series of small parts at a time.