CO2argon

CO2argon is a binary gas mixture consisting of carbon dioxide (CO2) and argon (Ar). The proportions of these gases can vary depending on the specific application. This mixture is commonly used in the welding industry, particularly in gas metal arc welding (GMAW), also known as MIG welding. In this context, it acts as a shielding gas.

The primary function of CO2argon as a shielding gas is to protect the molten weld pool from atmospheric contamination. The atmosphere, primarily composed of nitrogen and oxygen, can react with the molten metal, leading to porosity, reduced strength, and brittle welds. The CO2argon mixture displaces the surrounding air, creating an inert atmosphere around the arc and the weld.

The presence of CO2 in the mixture contributes to arc stability and influences the weld bead profile. It also provides a degree of deoxidation and cleaning action on the base metal. Argon, being a noble gas, is highly inert and is a fundamental component in many shielding gas mixtures due to its effectiveness in preventing oxidation. The specific ratio of CO2 to argon is chosen to optimize welding characteristics for different metals and welding conditions. For instance, higher CO2 content can lead to deeper penetration and a more forceful arc, often used for welding carbon steels. Lower CO2 content or higher argon content is typically used for stainless steels and aluminum alloys.