Which shielding gas is commonly used to protect steel welds?

Carbon dioxide is commonly used as a shielding gas in welding, particularly for welding steel. It effectively protects the molten weld pool from atmospheric contamination, which can lead to defects in the weld. When using carbon dioxide, the gas forms a stable arc and delivers good penetration while also being cost-effective.

In many applications, especially in MAG (Metal Active Gas) welding processes, carbon dioxide is favored due to its ability to produce strong, high-quality welds on steel and its availability. Its properties allow for better arc stability and heat input control, creating welds with favorable mechanical properties.

It’s important to understand that while other gases like argon and helium have their own applications in welding (with argon being more suitable for non-ferrous metals and helium being used in specific TIG weld situations), carbon dioxide stands out for common steel welding tasks due to its effectiveness and efficiency. Oxygen, though utilized in some cutting processes, is not suitable as a shielding gas for welding, as it can lead to oxidation and poor weld integrity.