Argon-carbon dioxide shielding gas mixture
An active gas mixture of argon and carbon dioxide that optimizes arc stability and controls penetration during GMAW welding.
Argon-carbon dioxide mixtures are the standard for MAG welding of structural steel. Argon stabilizes the arc and ensures a calm droplet transfer, while CO2 provides good penetration and makes the weld pool more fluid. If there's too little CO2, the arc becomes unstable and you get lack of fusion. If there's too much, it spatters heavily and you burn off alloying elements, making the weld porous and the seam brittle. The exact mixture depends on the material and position, but a standard mixed gas with a medium CO2 content covers most workshop cases. Just adjust pressure and flow rate so the arc burns smoothly and no air gets to the weld pool.