Procedure for Liquid Penetrant examination
LIQUID PENETRANT EXAMINATION (PT) Pentrant Testing is surface defects detection method, the method can be used on any material ( i.e: Ferrous/ non-ferrous, conductive/ non conductive, metals/ non metals) But PT is limited to materials having porous surface or very rough surface. PT can be carried out on castings, raw material, machined faces and weld joints. It is more often used in Austenitic Stainless Steels, where MPI inspection is not practically possible. Most standards insist that the penetrant materials used, should not contain contaminants that spoil the quality of weld and metals.( contaminants such as Sulphur, Chlorine & halogens ) Penetrant materials are mostly suitable for materials with surface temperature less than 52°C. Therefore the weld has to allowed to cool before carrying out PT test on it. Liquid penetrant testing principle Any PT inspection on elevated temperature (temperature other than 4°C to 52°C), should have special ...