Couplings inspection by active thermography

Coupling inspection is a key part of the manufacturing process of Oil&Gas components to ensure high quality products. Nowadays, the most common NDT inspection methods for coupling are magnetic particle testing and dye penetrant testing. However, Infrared thermography offers fast and contactless inspections in metal parts components enhancing the possibilities to automate the inspection of the couplings. In this work two infrared inspection methods based on Line Laser scanning thermography (LLST) and Eddy Current Pulsed Thermography (ECPT) are proposed to inspect the couplings. In order to do that, a custom made thermal imaging processing algorithm has been developed for each inspection method. The best strategy to inspect the couplings is analysed according to the experimental tests performed in automated test benches. The results of the study show the potential of the active thermography as a base of an automatic system capable to identify cracks all over the coupling surface.