Arc pressure and fluid flow during alternating shielding gases. Part 2: arc force determination
Arc pressure and fluid flow during alternating shielding gases. Part 2: arc force determination
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DOI：
10.1179/1362171813y.0000000141
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发表时间：
2013-10
影响因子：
3.3
通讯作者：
S. Campbell;A. Galloway;N. McPherson
中科院分区：
文献类型：
--
作者：
S. Campbell;A. Galloway;N. McPherson
交替保护气体过程中存在的保护气体的瞬态变化在液态焊接金属内产生动态作用。据报道，当存在氩气和氦气时，由于作用在焊缝金属上的各种力，流矢量方向相反；然而，没有提供任何数据来证实这一说法。这部分研究评估了使用氩气和氦气时作用在液态焊缝金属上的各种力，并讨论了它们的影响。经确定，对于电弧力和洛伦兹力，氩气在中心区域产生比氦气更大的垂直向下的力。然而，由于等离子体剪切应力和马兰戈尼对流，氦气在池表面产生的径向向外力比氩气更大。此外，氦气的浮力（即焊缝金属中心部分垂直向上的力）更大。
The transient variation of the shielding gas present in the alternating shielding gas process produces a dynamic action within the liquid weld metal. Flow vectors opposite in direction have been reported due to the various forces acting on the weld metal when argon and helium are present; however, no data have been provided to substantiate this claim. This part of the study evaluates the various forces acting on the liquid weld metal when using argon and helium, and their effects are discussed. It was determined that argon produces a greater vertically downward force in the central region than does helium for both the arc force and Lorentz force. However, helium produces a greater radially outward force at the pool surface than does argon due to plasma shear stress and Marangoni convection. In addition, the buoyancy force, i.e. the vertically upward force in the central portion of the weld metal, was greater for helium.