On the Effectiveness of Rotary Degassing of Recycled Al-Si Alloy Melts: The Effect on Melt Quality and Energy Consumption for Melt Preparation

The effectiveness of rotary degassing on the defect formation and mechanical properties of the final casting of aluminium alloy EN AC 46000 was investigated, along with its impact on the energy consumption in the casting furnace. In the melt preparation prior to casting, the molten metal is usually transported from the melting furnace to the casting furnace with rotary degassing as a cleaning procedure. Under the conditions of this specific study, negligible degradation was observed in the mechanical properties of the final cast component in an aluminium EN AC 46000 alloy after removing the rotary degassing step in the process. Furthermore, removing the rotary degassing step led to a reduced temperature drop in the melt, thus minimizing the need for reheating (energy consumption) by up to 75% in the casting furnace. The reduced energy consumption was up to 124,000 kWh in yearly production in a 1500 kg casting furnace. The environmental impact showed a similar to 1500 kg reduction in CO2 for one 1500 kg electrical casting furnace in a year.