What is the role of shielding gas in the welding process described by a WPS?

• A. It accelerates corrosion of weld.
• B. It protects the molten weld pool from atmospheric contamination during welding.
• C. It acts as a flux for cleaning.
• D. It colors the weld.

Answer: (B)

Shielding gas creates a protective atmosphere around the molten weld pool, keeping atmospheric air—oxygen, nitrogen, and moisture—from contaminating the weld as it cools and solidifies. This prevents oxidation, porosity, and hydrogen-related defects, helping achieve proper strength and bead quality. The WPS specifies which gas and flow rate to use because different gases and mixtures influence arc stability and penetration for the given material and process. The other options don’t fit: shielding gas does not accelerate corrosion, is not a cleaning flux, and does not color the weld.