Operational constraints on the DC induction heating of aluminum billets

Purpose – The purpose of this paper is to analyse the heating process of an aluminum billet rotating in a static magnetic field produced by optimized supercoducting coils. Design/methodology/approach – In order to meet the technical specifications of industrial heating, many processes with low speed in the given high magnetic field have been simulated. The mechanical stresses in the billet are examined by taking into account the temperature dependence of the mechanical properties. Findings – The main heating parameters, i.e. heating time, average temperature and temperature homogeneity, are evaluated for different values of angular velocity. The simulation results show that an optimal angular speed can be chosen with respect to the heating time. Research limitations/implications – The mechanical stress in the billet due to weight, centrifugal effects, applied torque and resonance is examined by taking into account the weakening of the material properties with the increase of temperature. The practical limits of the heating process are evaluated; while resonance does not seem to be a concern, the safety against yielding, in order to avoid plastic deformation of the billet during the heating, seems to be a constraint. Practical implications – DC induction heating of aluminum billet using superconducting magnets can be done fulfilling the specifics of the industrial processes. Originality/value – The operational and mechanical constraints on a high-efficiency DC induction heater for aluminum billets using superconducting coils are investigated.