Abstract A method of controlling droplet transfer by plasma arc was proposed to solve the problem that cathode spot force hindered the transition of cathode droplet under high current of twin-wire indirect arc (TWIA) in skew-coupling arc (SCA) welding. The effects of the plasma arc on droplet transfer were analyzed from the perspectives of plasma arc current (PAC) and plasma gas flow rate (PGFR). The current-voltage waveform, arc shape and the transition process of droplet were studied by using an electric signal and high-speed camera acquisition system. The results show that controlling droplet transfer by the plasma arc is feasible and effective in the SCA welding. With the increase of the PAC, the degree of the plasma arc deflection increased, and increasing the PGFR has a shrinkage effect on the top of the SCA. Increasing the PAC or the PGFR made the TWIA current vary in a small range, and the plasma arc voltage increase. Increasing the PGFR is more effective to promote the transition of cathode droplet than increasing the PAC, because the plasma fluid force of the TWIA on cathode droplet is enhanced by the double axial thrust of the plasma arc and the TWIA. The cooling effect of the plasma gas on anode droplet weakens the promoting effect of the plasma gas on the transition of anode droplet. The existence of the fluid beam hanging at the cathode wire is important to improve the transition of cathode droplet. The PGFR and the PAC could be cooperatively adjusted to promote the transition process of anode and cathode droplet.

中文翻译：

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等离子主弧对斜耦合弧焊熔滴转移的影响

摘要 为解决斜耦合电弧（SCA）焊接中双丝间接电弧（TWIA）大电流下阴极点力阻碍阴极熔滴转移的问题，提出了一种等离子弧控制熔滴转移的方法。从等离子弧电流（PAC）和等离子气体流速（PGFR）的角度分析了等离子弧对液滴转移的影响。利用电信号和高速摄像机采集系统研究了液滴的电流电压波形、电弧形状和转变过程。结果表明，通过等离子弧控制熔滴转移在SCA焊接中是可行和有效的。随着PAC的增加，等离子弧偏转程度增加，增加PGFR对SCA顶部有收缩作用。增加PAC或PGFR使TWIA电流在小范围内变化，等离子弧电压增加。增加 PGFR 对促进阴极液滴的转变比增加 PAC 更有效，因为等离子弧和 TWIA 的双轴向推力增强了 TWIA 对阴极液滴的等离子体流体力。等离子气体对阳极液滴的冷却作用减弱了等离子气体对阳极液滴转变的促进作用。悬挂在阴极丝上的流体束的存在对于改善阴极液滴的过渡很重要。PGFR 和 PAC 可以协同调节以促进阳极和阴极液滴的转变过程。增加 PGFR 对促进阴极液滴的转变比增加 PAC 更有效，因为等离子弧和 TWIA 的双轴向推力增强了 TWIA 对阴极液滴的等离子体流体力。等离子气体对阳极液滴的冷却作用减弱了等离子气体对阳极液滴转变的促进作用。悬挂在阴极丝上的流体束的存在对于改善阴极液滴的过渡很重要。PGFR 和 PAC 可以协同调节以促进阳极和阴极液滴的转变过程。增加 PGFR 对促进阴极液滴的转变比增加 PAC 更有效，因为等离子弧和 TWIA 的双轴向推力增强了 TWIA 对阴极液滴的等离子体流体力。等离子气体对阳极液滴的冷却作用减弱了等离子气体对阳极液滴转变的促进作用。悬挂在阴极丝上的流体束的存在对于改善阴极液滴的过渡很重要。PGFR 和 PAC 可以协同调节以促进阳极和阴极液滴的转变过程。等离子气体对阳极液滴的冷却作用减弱了等离子气体对阳极液滴转变的促进作用。悬挂在阴极丝上的流体束的存在对于改善阴极液滴的过渡很重要。PGFR 和 PAC 可以协同调节以促进阳极和阴极液滴的转变过程。等离子气体对阳极液滴的冷却作用减弱了等离子气体对阳极液滴转变的促进作用。悬挂在阴极丝上的流体束的存在对于改善阴极液滴的过渡很重要。PGFR 和 PAC 可以协同调节以促进阳极和阴极液滴的转变过程。