Discussion of the Effect of Shielding Gas and Conductivity of Vapor Core on Metal Transfer Phenomena in Gas Metal Arc Welding by Numerical Simulation
Discussion of the Effect of Shielding Gas and Conductivity of Vapor Core on Metal Transfer Phenomena in Gas Metal Arc Welding by Numerical Simulation
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DOI：
10.1007/s11090-020-10102-1
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发表时间：
2020-07-14
影响因子：
3.6
通讯作者：
Asai, Satoru
中科院分区：
文献类型：
--
作者：
Ogino, Yosuke;Hirata, Yoshinori;Asai, Satoru
熔化极气体保护焊在许多工业领域中是必不可少的。在此过程中，各种保护气体的使用，并显着影响电弧等离子体和金属转移的行为。在这项研究中，这些行为与各种保护气体进行了数值研究。此外，还讨论了金属蒸气电导率的影响。模拟结果表明，当电弧电流大于240 A时，采用Ar气体时，熔滴过渡模式为球状过渡模式;当电弧电流为300 A时，采用CO（2）气体时，熔滴过渡模式为球状过渡模式。计算结果表明，焊丝端部附近的电流路径决定了熔滴的行为。使用Ar气体时，电流路径被展开，覆盖熔化的焊丝，而使用CO（2）气体时，电流路径集中在熔化的焊丝的底部。因此，为了实现喷雾转移，电流路径需要在导线尖端处扩展;然而，如果扩展过度，则转移模式变为流转移。为了研究金属蒸气的影响，采用伪金属蒸气进行了数值实验。即使使用CO（2）气体，金属蒸气的电导率也低，因此电流路径不集中在熔融线材的底部，从而允许喷射转移。数值结果表明，通过控制金属蒸气的电导率，可以调控金属的过渡现象。
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 CO(2)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 CO(2)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 CO(2)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.