During GTAW, what is the purpose of using a trailing shield?

Using a trailing shield during Gas Tungsten Arc Welding (GTAW) plays a vital role in protecting the weld area from oxidation. When welding, the heat generated can cause the surrounding air to react with the molten metal in the weld pool, leading to undesirable oxide formations that compromise the integrity and quality of the weld. The trailing shield serves as a barrier that covers and protects the newly created weld from atmospheric exposure, thereby minimizing the risk of oxidation and ensuring a cleaner, stronger weld.

This protects the weld area not only from oxygen but also from other contaminants that can cause defects in the weld, such as nitrogen and moisture. By maintaining a shielded environment, the quality of the finished weld is significantly enhanced, leading to improved mechanical properties and appearance.

Understanding the function of the trailing shield is crucial for welders, especially in applications where the integrity of the weld is critically important, such as in aerospace or pressure vessel fabrication.