Argon-Helium Mixed Gas Thermal Conductivity
Mixing helium into argon increases thermal conductivity, leading to a broader penetration profile and higher arc voltage. This helps with conductive materials.
Physicochemical Mechanism of Action
Helium is a very light gas with high diffusivity, significantly increasing the thermal conductivity of argon. This leads to faster temperature distribution in the shielding gas and improves cooling efficiency.
Metallurgical Relevance & Risks in Welding
For conductive materials like copper or thick aluminum plates, the temperature drop during welding can be severe. Increased thermal conductivity prevents this drop and helps ensure homogeneous cooling. This reduces the risk of cracking and improves the mechanical properties of the weld.
Workshop Practice & Instructions
For conductive metals, use an argon-helium mix with 75% helium and 25% argon. Make sure the gas is well mixed and the penetration profile is broader than with pure argon. An arc voltage of at least 10 mm is recommended.