Novel technique for the design of induction billet heaters

Induction billet heating is a well established industrial process for preheating prior to forging, rolling and extrusion. Existing methods of work coil design which are based on the assumption of an infinitely long solenoid and/or the use of a great amount of empirical data are not easily adapted to the design of nonuniform surface power densities. The design of coils to produce such power densities are very empirical at the present time. This paper describes the application of a novel proximity heating technique to design relatively easily, an induction billet heating work coil to give non-uniform surface power densities along a typical industrial workpiece. Theoretical predictions are correlated with practical measurements on typical industrial installations.