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.