What is the main shielding gas for GMAW?

The main shielding gas for Gas Metal Arc Welding (GMAW), also known as MIG (Metal Inert Gas) welding, is commonly carbon dioxide. While carbon dioxide is used on its own or in mixtures, it provides key benefits in welding, such as improving arc stability and enhancing penetration.

Carbon dioxide's capability to create a more fluid puddle and increased melting efficiency makes it well-suited for various welding applications, especially when welding thicker materials. Additionally, it is more cost-effective compared to other shielding gases.

Though other gases like argon are also used in GMAW, typically in mixtures with carbon dioxide to improve arc properties and control, carbon dioxide alone often serves as a primary shielding gas due to its unique properties. Helium and nitrogen are generally not used as the main shielding gases in GMAW for carbon-based steel due to their different physical and chemical interactions during the welding process.