How does thoriated tungsten behave when heated?

Thoriated tungsten behaves in a unique way when exposed to heat due to its composition, which includes thorium. When heated, thoriated tungsten does not melt easily, making it well-suited for high-temperature applications in welding. The key feature of thoriated tungsten is that it significantly improves arc stability, which is crucial for processes like Gas Tungsten Arc Welding (GTAW).

Although thoriated tungsten does produce a certain amount of radioactive dust when ground or machined, this aspect primarily relates to safety and handling rather than its behavior when heated. This feature can be concerning in terms of potential health risks and environmental regulations, but it does not affect the operational efficiency or performance of the tungsten itself during welding processes.

The enhancement of arc stability is critical for achieving a higher degree of control over the welding process, allowing for a more precise and stable arc, which is essential for high-quality welds. Therefore, when heated, while the production of radioactive dust is noteworthy, the correct answer emphasizes its beneficial property in improving arc stability, which is vital for effective welding performance.