What does the term 'clean' refer to when preparing tungsten electrodes?

In the context of preparing tungsten electrodes for Gas Tungsten Arc Welding (GTAW), the term 'clean' specifically refers to the method of chemical cleaning to eliminate surface contaminants. Tungsten electrodes must be free of any substances that could interfere with their performance during the welding process. Surface contaminants, such as oils, oxides, and other residues, can negatively affect the stability of the arc and the quality of the weld.

Chemical cleaning processes might involve solvents or other agents that can effectively remove contaminants without damaging the electrode material itself. This step is crucial because the presence of impurities on the tungsten can lead to poor electrical conductivity and may result in inconsistent welds.

While mechanical grinding is an important part of preparing tungsten electrodes (particularly for shaping and tapering), it does not necessarily ensure that surface contaminants have been completely removed. Additionally, applying a protective coating can interfere with the welding process instead of facilitating it, and polishing for a smooth finish is more about appearance than about ensuring adequate cleanliness for optimal welding performance. Therefore, the emphasis on the chemical cleaning process is vital for the effective preparation of tungsten electrodes.