Arc Performance Affected By Tungsten Electrode Organizational Structure

During the welding process, arc performance not only connects with power supply unit and the environmental conditions, it also depends largely on the tungsten electrode’s arc performance. Good arc performance directly determines the use and application range of tungsten electrodes. The organizational structure of the tungsten electrode has a certain impact on tungsten electrode’s arc performance. In general, the integrity and uniformity of the tungsten electrode structure will directly affect the arc performance. If tungsten electrodes inside has splitting, delamination, micro-cracks, voids, mezzanine or severe non-uniform grain structure, the arc process is instability. So it will occur arc breaking, arc blasting, drift, and the worst case will cause thermal and electric, conductivity decreased, so that electrode’s local will overheating, melting, deformation, reducing the arc performance. In addition, at high temperatures, the electrode structure is closely related to the chemical composition. At High temperature, the doped rare earth oxides is easily migration, evaporation, dilution resulting in recrystallization coarsening to cause cracks.

Organizational structure and chemical composition of the tungsten electrode can affect their physical and mechanical properties, thus affecting its arc performance. Tungsten electrode as an important part in welding tool should have good physical and mechanical properties, such as, high melting point, high boiling point, low vapor pressure, good thermal conductivity and electrical conductivity, high temperature strength and high recrystallization temperature and creep and other good properties. If the physical property and mechanical properties of the tungsten electrode is defective, then it can result in electrode deformation and melting during the welding, leading arc performance deterioration. Different type rare earth tungsten electrodes have different deformation resistance and high temperature resistance. In general, tungsten electrode doped with two rare earth oxides is better than pure tungsten electrode and tungsten electrode doped with three rare earth oxides is better than tungsten electrode doped with two rare earth oxides.

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