Abstract: An electric arc furnace has a chamber suitable for containing molten steel, a roof covering the chamber and for containing a mass of scrap steel, electrodes for melting the mass of scrap, and a supporting base. The base permits the chamber to oscillate around a horizontal axis of rotation. The roof and the chamber are counterprofiled in correspondence to the respective interface walls to create a rotary coupling with regard to the axis of rotation. The roof, during oscillation of the chamber, remains fixed with regard to the base as well as in a closed position with regard to the chamber.