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

熔化极气体保护焊（GMA焊）的熔滴过渡对焊缝和工艺的可靠性以及焊接缺陷和飞溅的产生都有影响。因此，金属转移的建模是长期以来GMA工艺理论研究和预测的目标。由于迄今为止使用的材料转移的模拟辅助研究的GMA焊接过程已经通过单独的、非耦合的模型进行了研究，因此基于该研究的结果仅限于基本信息，然而，该基本信息忽视了焊接过程的复杂物理相互作用。然而，由于对模型的单独考虑，不可能确定各个参数对焊接过程的影响。因此，为了更好地理解GMA焊接过程，有必要将联合收割机的离散模型合并为通用模型。以往的研究中，边界条件的设置忽略了焊接过程中的物理现象，导致计算结果不准确。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（如铁）和原子气体（如氩）被认为是代替合金和分子气体用于所有实际目的。本研究的目标之一是建立一个通用的模型，该模型基于物理-物理模型的耦合和扩展，有助于对GMA焊接中的金属过渡进行现实的预测。为此，阳极层模型耦合到流体体积模型，这是一个挑战。然后，通用模型可以用于进行模拟研究，以研究焊接过程中每个物理效应的意义。该研究项目的另一个目标是，在通用模型的帮助下，说明某些工艺参数和材料组合对焊接过程的影响。在这方面，考虑了作为填充金属和分子保护气体以及脉冲工艺的技术合金。该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.