Other industries began to adopt the liquid dye penetrant inspection method for inspections, eventually adding dye to make cracks more visible. The whiting would absorb oil from cracks present in the material, revealing their presence so that railroad personnel could identify and fix them. These early tests followed the oil and whiting method, in which a person first cleans a surface with an oil solvent and then applies chalk to the area (or another “whiting” material). Cracks (cracks from fatigue, hairline cracks, or grinding and quenching cracks)ĭye penetration inspections were first performed in the railroad industry in the early 20th century.Porosity on the surface of the materials.In these materials, inspectors will be using dye penetrant to look for defects like: Liquid dye penetrant testing is commonly used to inspect the surfaces of non-porous assets made out of ceramics, plastics, and metals, where inspectors will be looking at:

The procedure for a dye penetrant test relies on the principle of capillary action, which describes how fluids penetrate into cracks (or discontinuities) on the surface of a material. Inspectors use liquid dye penetrant testing to look for cracks on the surface of assets and materials.Īfter flowing the dye penetrant onto the surface they want to inspect, inspectors will then draw the liquid out using a chalk-like developer, and thus reveal any material defects that might be present on the surface. Here is a menu to help you navigate this guide: It falls into the non-destructive testing category of inspection methods, because inspectors can use it without permanently altering or damaging the object they’re inspecting. In this guide, we will use the terms dye penetrant and liquid dye penetrant interchangeably, following the alternate terms listed above.ĭye penetrant is one of the most commonly used inspection methods. Dye penetrant is a dye used by inspectors in dye penetrant inspections, an inspection method in which inspectors apply a dye or liquid to a surface to identify defects in it.ĭye penetrant is also commonly called liquid penetrant or liquid dye penetrant.Īlso, dye penetrant testing is also commonly called dye penetrant inspection (DPI), liquid penetrant inspection (LPI), liquid dye penetrant testing, liquid dye penetrant inspection, liquid penetrant testing (LPT), or simply penetrant testing (PT).

Liquid notes 1.1.0.4 crack