Which type of welding uses a shielding gas to protect the weld zone?

Gas Metal Arc Welding (GMAW) is the type of welding that employs a shielding gas to protect the weld zone. In GMAW, a continuous solid wire electrode is fed through a welding gun, and a shielding gas is simultaneously released. This inert or semi-inert gas serves to prevent contamination of the molten weld pool from atmospheric elements such as oxygen and nitrogen, which could adversely affect the quality and properties of the weld.

The use of shielding gas is essential in GMAW because it helps achieve clean and strong welds by creating an atmosphere that allows for proper fusion of the base metals without oxidation. This advantage makes GMAW particularly suitable for welding materials where a high degree of cleanliness and structural integrity is required.

In contrast, other types of welding listed do not inherently rely on shielding gas in the same manner. Arc welding, while a broad term that can include multiple processes, may not always utilize gas shielding. Shielded Metal Arc Welding (SMAW) uses a flux-coated electrode, which provides protection through the gaseous products of the electrode itself rather than an external shielding gas. Gas welding, on the other hand, typically uses a flame rather than a shielding gas and works differently than the processes that require a gas.