摘要

thorough understanding of the physical mechanisms responsible for humping bead formation in high speed GMAW (gas metal arc welding) is essential to improve the welding productivity in today's competitive manufacturing industries. Based on the experimental observing results, a mathematical model is developed to quantitatively analyze the forming mechanism of humping bead for high speed GMAW, considering both the momentum and heat content of the backward flowing molten metal in weld pools. One term related to the momentum of backward flowing molten metal is added to the equation of the weld pool surface deformation, and the heat content of overheated droplets is distributed within the layer covering the whole pool. The humping bead forming process and its dimension and 3-D geometry are numerically simulated under some welding conditions. It is found that the model can describe and characterize the humping formation in high speed GMAW quantitatively.