In which type of welding is the use of shielding gas most critical?

The use of shielding gas is most critical in Gas Metal Arc Welding (GMAW) because this welding process relies heavily on the shielding gas to protect the molten weld pool from atmospheric contamination. In GMAW, a continuously fed wire serves as both the electrode and filler metal, and the shielding gas (which is often argon, CO2, or a blend) has the primary role of preventing oxidation and other reactions that could weaken the weld.

The shielding gas envelops the weld area, ensuring a clean and stable environment for the welding arc. If the shielding gas flow is insufficient or interrupted, it can result in poor arc stability, increased spatter, and compromised weld quality, leading to defects such as porosity and reduced mechanical properties.

Other welding processes, like Shielded Metal Arc Welding (SMAW), do use some form of shielding, but this is already provided by the flux coating on the electrode, making the external shielding gas less crucial. In Gas Tungsten Arc Welding (GTAW), while shielding is important—primarily for protecting the tungsten electrode and the weld pool—it relies on inert gases, but the process is not as dependent on gas flow as GMAW. Submerged Arc Welding (SAW)