Iron pile projection

Iron pile projection is required for constructional and electro-magnetic reasons. The iron piles serve to guide and direct the magnetic flux outside the induction furnace coil. A transverse field is created at both ends of the induction coil, which must be “trapped” by the iron piles, so that the scatter field that would otherwise be created cannot inductively heat the steel constriction of the furnace body.
The iron pile projection at the top should be about the same as the distance between the nominal crucible diameter and the coil internal diameter. In the lower area, approx. 30% more projection is used. More accurate values can be obtained from the electrical data of the relevant furnace. In the case of a 5-t furnace with 3,000 kW, these dimensions are approx. 120 mm at the top and approx. 160 mm at the bottom. If the furnace is operated at 4,800 kW, dimensions of 150 and 200 mm may be required.