What does the "Th" in AWS electrode classification EWTh-2 represent?

The "Th" in the AWS electrode classification EWTh-2 stands for "Thoriated." This designation indicates that the tungsten electrode contains a percentage of thorium oxide, typically around 2% in the case of EWTh-2. The addition of thorium to the tungsten improves the electrode's performance by enhancing its electron emission characteristics, which contributes to better arc stability and a higher current-carrying capacity.

Thoriated tungsten electrodes are commonly used in Gas Tungsten Arc Welding (GTAW) because they provide a more controlled arc and can maintain a clean and consistent weld. The thorium content ensures that the electrode has a longer life and can withstand higher temperatures without degrading significantly. This makes it a preferred choice for welding applications involving materials such as stainless steel and nonferrous metals, where precise control of heat and arc characteristics is essential.