2. Electromagnetic Field in Workpieces with Flat Surfaces

This chapter deals with the induction or direct resistance heating of flat bodies. Analytical solutions are derived for some typical configurations in order to calculate the main process parameters, like active and reactive power in the workpiece and power sources distributions [1]. The chapter is subdivided into four paragraphs and in each paragraph the solution is provided both for induction and direct resistance heating. In the first paragraph, solutions are presented for heating bodies of infinite dimensions having linear material properties. In the second chapter the same geometrical configuration is studied for ferromagnetic bodies. In the third paragraph, the solution of the electromagnetic problem is firstly obtained for the induction heating of a two-layers slab, than a workpiece of rectangular cross-section with finite dimensions is taken into account in a longitudinal flux system. The direct resistance heating of a finite dimension cross-section is then discussed. The last paragraph details the induction and resistance heating of finite cross-section loads, evaluating the current distribution near to different shaped edges.