Determination of surface temperature, surface tension and entalphy of the material transfer from the electrode to the workpiece in GTAW for the system argon-iron

Summary form only given. The gas metal arc welding (GMAW) process is widely used due to its universal applicability, high deposition rate and automatic feeding of the filler material. However, in order to perform process optimization and further develop this welding technique a better understanding of the complex physical and chemical transactions is required. More thorough investigation is needed, in particular to describe the droplet formation, the detachment of the droplets and the interaction of the material transfer with the weld seam formation. Numerical simulation could provide new possibilities for process understanding and development. Unfortunately important thermophysical parameters are still missing to develop and validate accurate models. Such parameters are the geometry, temperature, viscosity and surface tension of the droplet and the weld pool as a function of the filler and base material, shielding gases and welding parameters. In previous diagnostic investigations mostly only one of these quantities was measured. Due to different types of welding processes and process settings, a comprehensive description on the basis of several diagnostic studies is not given. Sensitive analyses e.g. of the influence of the wire feed rate or the gas composition are almost completely missing.