GTAW Advanced Welding Practice Exam

Nitrogen’s usefulness in GTAW comes from its role as an austenite stabilizer in the weld metal. When nitrogen is dissolved in the molten weld pool, it promotes the stabilizing influence of the austenitic (FCC) phase, increasing the amount of austenite in the solidified weld. This leads to improved toughness and corrosion resistance in stainless steels and nickel-containing alloys, and can help reduce sensitization by limiting harmful carbide formation at grain boundaries. Shielding gas for GTAW is typically argon (sometimes with helium), so nitrogen isn’t used as the primary shielding gas. It isn’t a fluxing agent in GTAW either.