Which shielding gas is preferred for overhead GTAW welding?

For overhead Gas Tungsten Arc Welding (GTAW), the preferred shielding gas is argon, known for providing a stable arc and excellent protection against contamination. Argon effectively shields the weld area from atmospheric gases, which is crucial when working in overhead positions due to the increased risk of oxidation.

While helium is used in some specific GTAW applications for its high thermal conductivity and ability to create hotter arcs, it is less commonly chosen solely for overhead welding. In this position, the advantage of argon in terms of stability and ease of use outweighs the benefits that helium might offer.

Carbon dioxide and oxygen are not suitable shielding gases for GTAW processes, as they can lead to increased oxidation and porosity in the weld, undermining the quality and integrity of the weld joint. Therefore, argon is the most suitable choice for shielding in overhead GTAW applications.