What is the purpose of the shielding gas in GTAW?

The purpose of the shielding gas in Gas Tungsten Arc Welding (GTAW) is to protect the weld area from atmospheric contamination. During the welding process, it is crucial to prevent the molten weld pool from being exposed to gases present in the atmosphere, such as oxygen, nitrogen, and moisture. These contaminants can lead to defects such as porosity, inclusions, and overall weakening of the weld joint. By providing an inert environment, the shielding gas helps ensure the integrity of the weld and results in a cleaner, stronger bond between the base materials.

In GTAW, the most commonly used shielding gases are argon and helium, which are both inert and help create a protective atmosphere around the weld without reacting chemically with the molten metal. This inert gas envelope plays a vital role in maintaining the quality and performance of the weld.