Dye Penetrant Inspection

Liquid penetration inspection is a method that is used to reveal surface breaking flaws by bleed out of a coloured or fluorescent dye from the flaw. This technique can be used on any type of steel.

The Dye Penetrant Inspection technique is based on the ability of a liquid to be drawn into a “clean” surface breaking flaw by capillary action. After a period of time called the “dwell or soak”, excess surface penetrant is removed and a developer is applied. The developer acts as a “blotter”, it draws the penetrant from the flaw to reveal its presence. Coloured (contrast) penetrants require good white light while fluorescent penetrants need to be used in darkened conditions with an ultraviolet “black light”.

Dye Penetrant inspection can be used on any material. It is essential that the material is carefully cleaned first; otherwise the penetrant will not be able to get into the defect. If surface penetrant is not fully removed, misleading indications will result.

The Weld-Tech inspection team has qualified rope access technicians to carry out this NDT discipline without the need for scaffolding, suspension platforms and cradles. Following our inspections we produce detailed reports, including drawings and photos, and these can be supplied in whatever form is required.