What gas is commonly used for shielding in GTAW?

In Gas Tungsten Arc Welding (GTAW), argon is the most commonly used shielding gas due to its excellent inert properties and effectiveness in protecting the weld area from atmospheric contamination. Argon is a noble gas, meaning it does not react with the molten metal, helping to produce clean and high-quality welds. Its density provides a stable, inert cover that minimizes oxidation and contamination during the welding process, which is crucial for achieving the desired properties in the weld joint.

While helium is also used in some applications due to its ability to provide higher heat input and improve arc stability, argon remains the most widely preferred choice, especially for the welding of metals like aluminum and stainless steel. Oxygen is not suitable for shielding in GTAW, as it can lead to oxidation of the weld. Similarly, nitrogen can introduce undesirable properties into the weld pool, making it less favorable for use in shielding applications.