Shielding Gas Mixture
A defined combination of primary gases and active or inert additive components used to optimize weld penetration and droplet transfer.
Shielding gas mixtures usually consist of argon with an admixture, e.g. CO2 or oxygen. The gas displaces the air around the weld area so that the workpiece doesn't oxidize and the weld seam stays clean. Depending on the material and process, you choose the mixture: For steel, use an argon-rich mixture with CO2; for aluminum or stainless steel, rather pure argon or special mixtures without active gases. If the gas doesn't fit or the amount is wrong, you get pores in the seam, spatter, or a dirty surface. Too much CO2 makes the arc behavior more aggressive; too little shielding leads to oxidation. Set the gas flow so that you have a slight overpressure in the welding area – you'll notice that the seam stays bright and no slag or discoloration forms. Make sure the gas nozzle isn't clogged and the hose has no kinks, otherwise the torch will suck in air.