Which two inert gases are commonly used in Gas Tungsten Arc Welding?

In Gas Tungsten Arc Welding (GTAW), the most commonly used inert gases are argon and helium. These gases act as shielding gases that protect the tungsten electrode and the weld pool from contamination by atmospheric gases such as oxygen and nitrogen.

Argon is the most widely used gas for GTAW due to its availability, cost-effectiveness, and excellent shielding properties. It provides a stable arc and works effectively for various materials, including aluminum and stainless steel. Helium, on the other hand, offers higher heat input and is particularly useful when welding thicker materials or when a hotter arc is required. The combination of argon and helium can enhance penetration and improve heat transfer during the welding process.

The other options listed do not consist of the gases typically used in GTAW. While hydrogen can be used in some specialized applications, it is not considered an inert gas and can introduce risks of excessive oxidation. Oxygen and nitrogen, while involved in many other processes, are not suitable for shielding in GTAW as they can adversely affect the quality of the weld by promoting oxidation and contamination.