Argon-Carbon Dioxide Shielding Gas Mixture
Argon-CO2 mixture optimizes welding of structural steels by controlling droplet transfer and reducing porosity.
Physical and Chemical Mechanism of Action
The argon-carbon dioxide mixture (approx. 75% argon, 25% carbon dioxide) protects the weld seam from ambient moisture and metabolic reactions. The carbon dioxide ensures a more fluid droplet formation and improves the conductivity of the electrolyte, leading to a more stable welding process.
Metallurgical Relevance & Risks in Welding
An insufficient carbon dioxide content can lead to dry droplets and porosity. Too much carbon dioxide enlarges the grain and reduces the toughness of the steel. The correct concentration is crucial for a high-quality weld seam without cracks or hot cracks.
Workshop Practice & Operating Instructions
Use an argon-carbon dioxide mixture with a carbon dioxide concentration of 25%. Make sure the gas flow meter is set correctly and the weld seam is done in a dry environment. Fine-tuned humidity and controlled temperature of the weld pool are crucial.