Transverse flux induction heating of aluminum alloy strip

Transverse flux induction heating, an efficient electrical technique particularly suited to the continuous heat treatment of metal strip, is explained. Also described is a 1MW transverse flux inductor designed and built at the Electricity Council Research Centre, Capenhurst, and installed in a tension leveller line at Alcan Plate Ltd., Birmingham, UK. It has been successfully used for the continuous heat treatment of wide (1200-1250 mm) aluminum alloy strip, involving full and partial annealing at line speeds up to 2/ms as well as the solution treatment of certain high strength aluminum alloys. The advantages of this form of induction heating are compactness, controllability, hence ease of automation, and high efficiency. As a consequence, compared with existing batch and continuous heat treatment equipment, major economies in plant operation result due to reduced energy consumption as well as reduced capital and labor costs. The compactness of the technique allows the possibility of introducing transverse flux induction heat treatment furnaces into existing process lines.