Sensing weld pool geometrical appearance in gas–metal arc welding

Sensing and correlating the surface geometrical appearance of weld pool to the weld penetration are prerequisites for gas–metal arc welding (GMAW) process control. This paper focuses on vision-based sensing and determination of the weld pool geometrical appearance during the GMAW process. An experimental system has been developed to measure the weld pool geometry under different GMAW conditions. A special camera system, assisted by laser pulsation and a filter, was integrated with the developed image-processing algorithm to overcome the strong disturbances in GMAW. The shielding gas of 80% Ar + 20% CO2 was used to make bead-on-plate welds on low-carbon steel Q235 workpieces. The weld pool boundary with real dimensions was obtained for different GMAW conditions. The results provide a good foundation for describing the correlation of the weld pool surface geometry to the penetration.