Liquid penetrant inspection (PT) reveals surface flaws by the "bleed-out" of a penetrating medium against a contrasting background. This is done by applying penetrant to the pre-cleaned surface and flaw of the item being inspected.
The penetrant liquid will be drawn into any surface opening by capillary action. Following removal of excess penetrant an application of a developer reverses the capillary action and draws penetrant from the flaw. The resultant indications reveal the presence of the flaw so that it can be visually inspected and evaluated. NDTG provides the following services with this technique.
- Visible penetrants.
- Fluorescent penetrants.
- High Temperature penetrants