Development of a physical-mathematical model of the gas metal arc welding process for pulsed mode by using multicomponent filler materials and molecular gases

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The metal transfer in gas metal arc welding (GMA welding) have an influence on both weld seam and process reliability and appearance of weld defects or spatters. The modelling of metal transfer is therefore for a long time a goal for theoretical study and prediction of GMA process. Since the GMA welding process for the hitherto used simulation-aided research of the material transfer has been studied by separate, non-coupled models, the results which are based upon this research are limited to fundamental information which, however, disregards the complex physical interactions of the welding process. Due to the separate consideration of the models it has, however, been impossible to determine the influence which the individual parameters exert on the welding process. For this reason and for further understanding the GMA welding process it is necessary to combine separate models into general model.For previous researches, boundary conditions, through which the physical phenomena have been neglected, leading thereby to inexact results, have been set. Practice-oriented boundary conditions also were not considered. So far pure wire materials (for example iron) and only atomic gases (for example argon) were considered instead of the alloys and molecular gases used for all practical purposes. Furthermore, the impulse process was completely neglected.A goal of the research project consist of creating a such general model, based on a coupling and extension of mathematical-physical models that helps making realistic predictions of the metal transfer in GMA welding. For this, an anode layer model is coupled to the Volume-of-Fluid model, which represents a challenge. The general model can then be used to perform simulative studies in order to investigate the meaning of every single physical effect for the welding process. Another goal of the research project is, with help of the general model, to make statements about the influence of certain process parameters and material combinations on the welding process. In this, technical alloys as the filler metal and molecular shielding gases as well as pulsed process are taken into account. The results of this research project lead to a better understanding of the physical phenomena of the welding process - initially with practice-oriented boundary conditions - and make a targeted control possible.