In-Depth Induction Heating of Large Steel Slabs by Means of a DC Saturating Field Produced by Superconducting Coils

The feasibility of an innovative in-depth AC induction heating method for large steel slabs is investigated. Aside from the AC field, which induces the heating currents, a large DC magnetic field is also applied, which brings the material to saturation. Due to saturation, permeability is reduced by orders of magnitude and the penetration depth is drastically increased, thus enabling much faster and more uniform heating. In order to produce the field needed for the saturation of common steel workpieces, lossless DC superconducting magnets need to be employed. A possible layout of an AC induction heater employing magnetic saturation (saturated AC induction heater) is discussed. The conceptual design of the superconducting magnet needed is carried out based on present state-of-the-art superconducting materials. The performance of the saturated AC induction heater is numerically investigated and compared with the case without magnetic saturation.