Acoustic-Emission Procedure for Rejecting Defects in Multiple-Pass Girth Welds

Abstract

A procedure is proposed for rejecting girth welds based on an analysis of the main parameters of acoustic emission (AE) signals recorded during multiple-pass welding. The accuracy of locating AE signals recorded from defects and their filtering from noise and interference were ensured by the use of a modified tabular method and rejection grid. Normalized coefficients were calculated from the energy and amplitude of localized AE signals and used for in-process assessment of weld quality. Threshold values were determined for the normalized coefficients above which the weld is rejected. Defects in girth welds were identified using this procedure, and the possibility of determining defect hazardousness in real time was demonstrated.