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

气体保护焊(GMA焊)中的熔滴过渡对焊缝和工艺可靠性以及焊接缺陷或飞溅的外观都有影响。因此，熔滴过渡过程的模拟一直是GMA过程理论研究和预测的目标。由于迄今所使用的模拟辅助研究材料转移的GMA焊接过程是通过单独的、非耦合的模型来研究的，因此基于这一研究的结果仅限于基本信息，而忽略了焊接过程中复杂的物理相互作用。然而，由于对模型的单独考虑，无法确定各个参数对焊接过程的影响。为此，为了进一步了解GMA焊接过程，有必要将单独的模型组合成通用模型。在以往的研究中，设置了边界条件，通过这些边界条件可以忽略物理现象，从而导致结果不准确。以实践为导向的边界条件也没有被考虑。到目前为止，只考虑了纯金属丝材料(例如铁)和原子气体(例如Ar)，而不是用于所有实际目的的合金和分子气体。此外，脉冲过程被完全忽略。该研究项目的一个目标是建立这样一个通用模型，基于数学-物理模型的耦合和扩展，以帮助对GMA焊接中的熔滴过渡做出现实的预测。为此，阳极层模型被耦合到流体体积模型，这是一个挑战。然后，可以使用通用模型进行模拟研究，以调查焊接过程中每一种物理效应的意义。本研究项目的另一个目标是借助通用模型，阐述某些工艺参数和材料组合对焊接过程的影响。在这一过程中，考虑了作为填充金属的技术合金和分子保护气体以及脉冲过程。这一研究项目的结果有助于更好地理解焊接过程的物理现象--最初是以实践为导向的边界条件--并使有针对性的控制成为可能。

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.