What is the primary gas used in MIG welding?

The primary gas used in MIG welding is Argon. This inert gas is preferred because it effectively shields the molten weld pool from contamination with atmospheric gases, like oxygen and nitrogen, which can adversely affect the quality of the weld. Argon is particularly effective for welding non-ferrous metals such as aluminum and magnesium. Its ability to provide a stable and smooth arc makes it ideal for a variety of welding applications.

In certain applications, a mix of gases may be used to achieve specific results; for example, a blend of argon and carbon dioxide is common in some steel welding scenarios to help enhance penetration and improve the overall weld quality. However, pure argon is still the most commonly used gas in MIG welding due to its protective properties and versatility across various welding tasks.