What are balled or rounded ends of the tungsten used for?

The balled or rounded ends of the tungsten electrode in Gas Tungsten Arc Welding (GTAW) serve a specific function related to the welding of materials that have surface oxides. When the tungsten tip is rounded, it provides a cleaner arc and promotes better arc stability, which is particularly beneficial when welding materials like aluminum and magnesium that are prone to surface oxidation. This rounded shape helps to create a more intense, focused arc that effectively removes surface contaminants. As a result, the rounded tungsten enhances the cleaning action at the weld area, ensuring that the base material is properly prepared for a strong and effective weld.

While some options might touch upon related aspects of welding efficiency or heat management, they do not address the specific benefit provided by the balled tungsten in promoting a cleaning action, which is critical for successful welding on certain materials.