Which property of a tungsten electrode affects the welding arc stability in GTAW?

The material composition of a tungsten electrode plays a crucial role in determining the stability of the welding arc in Gas Tungsten Arc Welding (GTAW). Tungsten is known for its high melting point and excellent conductivity, which allow it to maintain a stable arc even when exposed to high temperatures during the welding process.

Different alloying materials can be added to tungsten to enhance certain properties, such as its ability to withstand high temperatures, maintain a clean arc, or reduce electrode wear. For example, some tungsten electrodes are alloyed with thorium or zirconium, which can improve the initiation and stability of the arc. The composition affects how well the electrode can conduct electricity and resist changes in arc length, both of which are critical for maintaining a stable welding arc.

In contrast, while the diameter, length, and surface finish of the tungsten electrode also contribute to welding performance, they primarily affect the arc's characteristics, such as the size and focus of the heat. However, the material composition significantly influences the intrinsic properties of the electrode that ensure consistent and stable arc behavior during welding operations.