Tungsten Electrode Surface Ablation of Argon Arc Welding

Tungsten electrode is an important part of argon arc welding. Besides, tungsten electrode plays an important role in arcing, welding quality and arcing stability. Operation at the high temperature tungsten electrodes will occurs in the mass loss, called electrodes ablation. And ablation can be divided into added oxide ablative and tungsten substrate ablation, and the added oxides include ThO2, CeO2, and La2O3 and so on. Because they melting point is lower than the tungsten substrate’s, so the ablation rate will faster. The ablation of added oxide in the electrode may cause the oxide content in the electrode surface reduction, resulting in hard to arcing or arcing unstable. So as we knew, added oxide in tungsten electrodes ablation in some degree greatly affects the properties of the arcing and the arcing stability of the argon arc welding. On the other hand, the tungsten substrate ablation mainly because of the hot tungsten electrode react with the surrounding environment or oxygen in the shielding gas, and produced oxide will deposit in the head of electrode to cause tungsten substrate ablation. Tungsten substrate ablation not only seriously affect the stability of the arcing, and will cause the deposited tungsten shedding, changing the composition of the welding content, affecting the quality of welding.

The experiment found that reducing tungsten electrode ablation not only can improve the life of the tungsten electrode, and can ensure the welding quality. And reducing the tungsten electrode ablation there are some approaches as following:

1. To improve the purity of the inert gas, which at the same time reducing the oxygen content;
2. In the welding process, to use appropriate protective gas flow;
3.To select appropriate and well-torch welding gun and electrode size;
4. To use tungsten electrode which doped nano-oxide.

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