Argon-helium shielding gas mixture
Argon-helium mixture is a shielding gas that combines argon's stability with helium's thermal conductivity. It produces deeper penetration and faster welding on thick workpieces.
Physical-Chemical Mechanism of Action
An argon-helium mixture consists of a blend of argon (approx. 70%) and helium (approx. 30%). Argon protects the weld seam from oxidation and contamination, while helium increases thermal conductivity and makes the penetration deeper. This leads to faster cooling of the weld zone.
Metallurgical Relevance & Risks in Welding
Using an argon-helium mixture can lead to better mechanical properties of the weld seam, as it minimizes oxidation and contamination. However, the gas must be used in the correct concentration to avoid unwanted effects such as increased stresses or altered microstructures.
Workshop Practice & Action Instructions
Use argon-helium mixture for thick-walled steels and heavy metals to achieve deep penetration and fast welding speed. The gas supply should be set to ensure a concentration of 70% argon and 30% helium. Make sure to properly shield the weld zone to keep the gas effective.