Elemental Development of Metal Melting by Electromagnetic Induction Heating Using Superconductor Coils

The billet heating technique by rotating conductive material in a magnetic field for aluminum extrusion has been reported, but metal melting technology by the induction heating with the dc magnetic field has not. Further complex geometries of aluminum profiles are formed by the casting that requires highly efficient metal melting technology. In order to verify the capability of induction heating using dc superconductor coils for metal melting in the casting process, we performed a metal melting experiment with the small examination equipment in a magnetic field. The small examination equipment consists of a motor, a heat insulation structure, a rotating shaft, a specimen holder, a frame, and others. An aluminum pipe of about 0.77 kg, where its outer diameter was 180 mm and its inner diameter was 170 mm, was put into the examination equipment. A dc magnetic field, ranging from about 1 T at the nearest point to 0.4 T at the furthest point, was applied to the pipe by the superconductor magnet. The temperature of aluminum exceeded 500 °C within 2 min by the rotation of the pipe at 800 r/min. Aluminum melting in the sample holder was observed after the rotation of 1200 r/min in 90 s, and some amounts of melted aluminum rose over the sample holder and sputtered out by centrifugal force. These results indicate that induction heating with the superconductor coils can supply melting metal of required amount in a short time.