Abstract

The results of a study of aluminum welding by reverse-polarity direct current in a medium of protective gases (argon) at the stage of the binding and formation of the pool of melted metal are presented. It is shown that cathode spots in a current range of 5–50 A and action time of up to 1 s do not clean the cathode film from the aluminum surface but remelt the surface layer. The types of cathode spots that form on the aluminum surface are analyzed. It is shown that evaporation is the main mechanism for the removal of the oxide film. A new mechanism of the interaction between a welding arc discharge an aluminum surface is proposed: the main role in the formation of the welding pool is played by an immobile cathode spot, which, on the one hand, evaporates the oxide film and, on the other, intensely heats the surface layer of the aluminum to the phase transition due to high heat density. After the formation of the welding pool, the immobile cathode spot disappears, followed by the diffusion regime of welding arc burning. The regime is characterized by a uniform distribution of the electric field over the length of the discharge gap with a low potential decrease and occupies almost whole interelectrode gap.

中文翻译：

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反极性直流焊接电弧放电与铝表面相互作用的新机理

摘要

给出了在熔融金属的结合和形成阶段在保护气体（氩气）介质中通过反极性直流电进行铝焊接的研究结果。结果表明，在5–50 A的电流范围内的阴极斑点和长达1 s的作用时间不会从铝表面清除阴极膜，而是使表面层熔化。分析了在铝表面上形成的阴极斑点的类型。结果表明，蒸发是去除氧化膜的主要机理。提出了一种新的电弧与铝表面之间的相互作用的机理：在固定的熔池中起主要作用的是固定的阴极斑点，该阴极斑点一方面蒸发了氧化膜，另一方面使氧化膜蒸发。其他，由于高的热密度，强烈地将铝的表面层加热至相变。焊池形成后，固定的阴极点消失，随后是焊接电弧燃烧的扩散状态。该方案的特征在于电场在放电间隙的长度上的均匀分布，并且电势降低低，并且几乎占据了整个电极间间隙。