Fluorescent Penetrant Testing
Penetrant testing with fluorescent media is a surface inspection method where a capillary-active dye makes open material separations visible by color indication under UV light. This enables precise detection of cracks or corrosion.
Physicochemical mechanism of action
A fluorescent penetrant is applied to the material surface. Under UV light, the dye reacts with the capillary-active liquids in the cracks and forms a visible color indication. This reaction is specific to the chemical composition of the penetrant and the material separation.
Metallurgical relevance & risks in welding
Penetrant testing with fluorescent penetrants is especially important after welding to ensure that no cracks or corrosion exist in the weld areas. Missing or incomplete inspections can lead to safety risks and additional costs due to rewelding or replacement of components.
Shop practice & instructions
1. Prepare the material by cleaning it and removing any dirt or paint.
2. Apply the fluorescent penetrant liquid to the material surface.
3. Expose the material to a UV light beam for a few seconds (usually 10–30 s).
4. Observe the surface for color indication, which appears at cracks and corrosion damage.
5. Document all found defects thoroughly.