“RoWaMag”: Design and Test of the HTS Magnet and the Cryogenic System of the Robust and Low Maintenance Magnetic Billet Heater

In the framework of the German project “RoWaMag”, a low-maintenance magnetic billet heater with a REBCO magnet has been developed, built and tested. Magnetic billet heaters can be used in the manufacture of semi-finished metal products where metal billets need to be annealed at temperatures up to 1100°C in order to soften the materials for further forming. By rotating the metal billet in a DC magnetic field produced by a superconducting magnet, higher efficiencies than for conventional induction heaters with high AC losses can be achieved. The conduction-cooled RoWaMag magnet with an iron yoke is designed to generate a magnetic field of 600 - 700 mT at the center of the heating axis of metal billets with a maximum length of 750 mm and a diameter up to 225 mm. The HTS magnet consists of three rectangular double pancake coils made of 3110 m REBCO tape from Theva. The operating current is 505 A. In this paper we present the design and construction of the HTS magnet, the HTS current leads and the cryogenic system of the magnetic billet heater. We present test results for the magnet and the cryogenic system and give an outlook to the final project stage with integration and operation of the magnet in the billet heater.