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

气体保护金属电弧焊中的金属转移对焊缝和工艺的可靠性以及焊缝缺陷或飞溅物的出现都有影响。因此，金属转移的建模一直是GMA过程理论研究和预测的目标。由于迄今为止使用的GMA焊接过程的材料传递模拟辅助研究是通过单独的非耦合模型进行的，因此基于该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，由于模型的单独考虑，不可能确定单个参数对焊接过程的影响。因此，为了进一步了解GMA焊接过程，有必要将单独的模型合并为总体模型。在以往的研究中，边界条件被忽略，从而导致不精确的结果。也没有考虑面向实践的边界条件。到目前为止，纯金属丝材料（例如铁）和原子气体（例如氩气）被认为是代替合金和分子气体用于所有实际目的。此外，脉冲过程完全被忽略。该研究项目的目标之一是创建这样一个通用模型，该模型基于数学-物理模型的耦合和扩展，有助于对GMA焊接中的金属转移进行现实的预测。为此，需要将阳极层模型与流体体积模型相耦合，这是一个挑战。然后，通用模型可以用于进行模拟研究，以调查焊接过程中每一个物理效应的含义。研究项目的另一个目标是借助通用模型，说明某些工艺参数和材料组合对焊接过程的影响。在此过程中，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工艺。这个研究项目的结果导致更好地理解焊接过程的物理现象-最初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.