Active Shielding Gas
Active welding shielding gas is a mixture of argon, carbon dioxide, and oxygen that acts actively in arc fusion welding. It improves droplet formation and sidewall wetting, leading to better fill and fewer pores.
Physico-Chemical Mechanism of Action
Active shielding gases contain argon as a carrier gas with carbon dioxide (CO2) and oxygen (O2). CO2 reacts with the metal to form a fusible layer that stabilizes the droplet. The O2 content improves sidewall fusion through oxidative reactions.
Metallurgical Relevance & Welding Risks
Using active gas improves weld quality by reducing porosity and enhancing fill. If the additives are missing or improperly proportioned, this can lead to uneven sidewall fusion and poor fill.
Workshop Practice & Instructions
Use an active gas mixture with 3-5% CO2 and 1-2% O2. Make sure the gas is mixed correctly and the machine is set to ensure optimal droplet transfer. Continuously monitor the gas supply and correct as needed.