Also known as Dye Penetrant & Liquid penetrant testing, PT relies on the physics of “capillary action” to enhance surface and slightly sub surface defects in parent and weld metal.

Most commonly used on non ferro magnetic metals such as Austenitic stainless steel and aluminium, PT can also be used on ferro magnetic steels where magnetic particle inspection is impractical.

Defects such as cracks and porosity are easily detected, by providing a “bleed though” colour contrast between the red dye penetrant and the developer white background.

PT is a surface method of testing mandatory under most welding standards of non ferro magnetic materials, where testing is specified.