Non-destructive evaluation of resistance projection welded joints (RPW) by flash thermography

Pulsed thermography is a well-known thermographic method used as nondestructive control for detecting defects and evaluating the quality of components. One of the most challenging application is the development of thermographic non-destructive methods on thin welds for quality control, in order to overcome the limits of commons non-destructive methods such as ultrasound tests (UT). In the present work, pulsed thermography in reflection mode with flash lamps excitation, post-processed by pulsed phase thermography (PPT), has been used on resistance projection welded joints (RPW). A set of RPW specimens has been produced according to a factorial plan and a procedure to identify welding parameters by analysing the phase profile has been developed. The results have been analysed by using the ANOVA and the features extracted have been verified.