What is the composition of a green tungsten electrode?

A green tungsten electrode is composed of pure tungsten. This type of electrode is primarily used for applications that require minimal contamination, such as in welding aluminum and magnesium alloys. Pure tungsten electrodes have a high melting point and are capable of providing a stable arc, which is essential for achieving clean and precise welds.

While the other options involve tungsten compounds or mixtures, they serve different purposes and applications. Wolfram carbide is not an electrode material; rather, it is a hard material often used in cutting tools. Tungsten with copper is generally used for specific applications that require enhanced thermal and electrical conductivity, while tungsten with thorium is used in specific types of welding due to its improved electron emission and arc stability characteristics.

The use of pure tungsten electrodes (green) ensures that there are no additives that could negatively affect the weld quality in sensitive applications, making it the appropriate choice in specific welding scenarios where purity is critical.