Which substance is commonly utilized as a shielding gas in gas welding techniques?

Argon is commonly utilized as a shielding gas in gas welding techniques, particularly in processes such as Metal Inert Gas (MIG) welding and Tungsten Inert Gas (TIG) welding. The primary purpose of a shielding gas is to protect the molten weld pool from atmospheric contamination, which can lead to defects in the weld. Argon fits this role well due to its inert properties, as it does not chemically react with the molten metal or the surrounding environment, allowing for a cleaner and stronger weld.

Using argon helps maintain a stable arc during welding and ensures a consistent heat input, resulting in better weld quality. Its density also means it effectively blankets the molten pool, preventing oxidation and other contamination that can occur with exposure to oxygen and moisture in the air.

Other gases, such as helium, are also used but typically in combination with argon or in specific applications where higher heat is required. Nitrogen and ozone do not serve the same purpose in gas welding; nitrogen can actually cause nitriding effects that can weaken the weld and ozone is a reactive gas that does not provide the necessary inert protection during the welding process.