Which statement about shielding gas in GTAW is true based on the material?

• A. It removes weld fumes
• B. It shields from UV radiation
• C. It keeps air away from the hot tungsten and molten weld metal
• D. It primarily cools the workpiece

Answer: (C)

Shielding gas in GTAW creates a protective envelope around the tungsten electrode and the molten weld pool, displacing air so oxygen, nitrogen, and moisture can’t contact the hot metal. This prevents oxidation and contamination of both the electrode and the weld, helping maintain arc stability and a clean, strong weld. The gas (usually argon or helium, sometimes a mix) is chosen for its inert or mildly reactive nature and its ability to support the desired heat and shielding quality. This function isn’t about removing fumes or shielding from UV radiation, and it doesn’t primarily cool the workpiece—the key role is to keep air away from the hot tungsten and molten metal.