Dye penetrant inspection

Read more about our Dye Penetrant Inspection services below:

What is Dye Penetrant Inspection?

Dye penetrant inspection (DPI), also called liquid penetrate inspection (LPI) or penetrant testing (PT), is a widely applied and low-cost inspection method used to locate surface-breaking defects in all non-porous materials (metals, plastics, or ceramics).

How does Dye Penetrant Inspection Work?

One of the oldest and simplest methods of Non-Destructive Testing, dating back as far as the 19th century. Dye Penetrant Inspection is used to detect any surface connected discontinuities such as cracks from fatigue, quenching, and grinding, as well as fractures, porosity, incomplete fusion, and flaws in joints.
Based on capillary action, low surface tension fluid penetrates into clean and dry surface-breaking discontinuities. After enough time has passed for the penetrant to mould into any flaw the excess penetrant is removed and a developer is applied. The developer helps to draw penetrant out of the flaw where an invisible indication becomes visible to the inspector. Depending on the type of dye used, inspection is performed under ultraviolet or white light.
The penetrant may be applied to all non-ferrous materials and ferrous materials, although for ferrous components magnetic-particle inspection is often used instead for its subsurface detection capability