Gas metal arc welding is indispensable in many fields of industry. In this process, various kinds of shielding gas are used, and they significantly affect the behaviors of the arc plasma and metal transfer. In this study, these behaviors with various kinds of shielding gas are numerically investigated. In addition, the influence of the electrical conductivity of the metal vapor is discussed. Simulation results show that with Ar gas, spray transfer occurs at an arc current of more than 240 A, and with CO2 gas, the transfer mode is globular, even at an arc current of 300 A. The calculation results show that the current path near the wire tip critically determines droplet behavior. With Ar gas, the current path is spread out, covering the molten wire, whereas with CO2 gas, the current path is concentrated at the bottom of the molten wire. Therefore, to achieve spray transfer, the current path needs to be spread at the wire tip; however, if the spreading is excessive, the transfer mode becomes streaming transfer. To investigate the influence of the metal vapor, a numerical experiment using pseudo metal vapor was carried out. Even with CO2 gas, the electrical conductivity of the metal vapor was low, and thus the current path was not concentrated at the bottom of the molten wire, allowing spray transfer. The numerical results show that metal transfer phenomena can be regulated by controlling the electrical conductivity of the metal vapor.

中文翻译：

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数值模拟探讨保护气体和蒸气芯电导率对气体保护金属电弧焊中金属转移现象的影响

在许多工业领域中，气体保护金属弧焊是必不可少的。在这个过程中，使用了各种保护气体，它们显着影响电弧等离子体和金属转移的行为。在这项研究中，对各种保护气体的这些行为进行了数值研究。此外，讨论了金属蒸气的电导率的影响。仿真结果表明，Ar气在240A以上的电弧电流下发生喷雾转移，CO2气即使在300A的电弧电流下也呈球状转移。计算结果表明，电流路径接近线尖关键地决定了液滴的行为。使用 Ar 气体，电流路径展开，覆盖熔化的焊丝，而使用 CO2 气体，电流路径集中在熔化焊丝的底部。所以，为实现喷雾转移，电流路径需要在焊丝尖端扩散；但是，如果传播过度，则传输方式变为流式传输。为了研究金属蒸气的影响，进行了使用假金属蒸气的数值实验。即使使用 CO2 气体，金属蒸气的导电性也很低，因此电流路径不会集中在熔丝底部，从而允许喷雾转移。数值结果表明，可以通过控制金属蒸气的电导率来调节金属转移现象。进行了使用伪金属蒸气的数值实验。即使使用 CO2 气体，金属蒸气的导电性也很低，因此电流路径不会集中在熔丝底部，从而允许喷雾转移。数值结果表明，可以通过控制金属蒸气的电导率来调节金属转移现象。进行了使用伪金属蒸气的数值实验。即使使用 CO2 气体，金属蒸气的导电性也很低，因此电流路径不会集中在熔丝底部，从而允许喷雾转移。数值结果表明，可以通过控制金属蒸气的电导率来调节金属转移现象。