Time–frequency diagram applied to stability analysis in gas metal arc welding based on acoustic emission

Abstract

Time–frequency diagram is applied to estimating the stability of gas metal arc welding process. A methodology has been developed to obtain indexes based on image processing of the spectrogram in order to evaluate the relationship between the spectrogram and the stability of process. The acoustic emission (AE) signals have been processed and characterised to obtain the spectrogram of the acoustic signals generated by arc. Statistical analysis of image generated by spectrogram and temporal parameters of AE signals has been used as a tool to obtain a method for stability evaluation. As a main result of the research, it demonstrates the effectiveness of the application of image processing of the time–frequency diagram for evaluating the stability in the welding processes. The results demonstrate the validity of this method to characterise the stability using the image characterisation.