Productivity Improvements in Industrial Twin-Roll Casting by Heat Loss Analysis Along the Process Chain

The main limitation in industrial twin-roll casting of aluminum with respect to productivity is heat removal from the melt in order to ensure complete solidification before the material leaves the roll gap. For this purpose a heat loss analysis was performed along the process chain starting at the melting furnace. By reducing heat losses in the launder system, filter box, and the ceramic nozzle it was shown that melt temperature can be decreased considerably at all stages. This leads to savings of energy and CO2 emissions. Furthermore, lower headbox temperatures reduce the heat to be diverted in the cooling system. This advantage can be directly converted into an increased strip speed. For example for alloy AA3003, a reduction in headbox temperature by 12 °C did increase the productivity by up to 9% in a full campaign. The findings are now consequently used in production.