Britannica Sources used in this answer

Why is argon commonly used in gas-shielded arc welding?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Welder in a blue uniform and protective helmet using shielded metal arc welding to join metal pieces, with bright sparks and smoke visible at the welding point. — welding Shielded metal arc welding.

Argon is commonly used in gas-shielded arc welding because it acts as an inert gas that protects the molten metal from the atmosphere.21

When metals are heated to their melting point, they often react rapidly with oxygen and other elements in the air, which can lead to the formation of oxide layers that prevent proper bonding and make the weld joint brittle. By flowing from an annulus surrounding the welding torch, argon creates a continuous stream that displaces the air from around the arc. Because it is chemically inert, it does not react with the metal but effectively shields the weld pool from contamination, ensuring a higher-quality, tougher weld deposit. Additionally, this process allows for higher efficiency and can be readily automated.12