The magnetic field induces eddy currents in the workpiece, and the electrical resistance of the piece to the flow of current causes the piece to heat up. The depth of heating is a function of the electrical frequency applied, the heating time and the power density applied to the component being heated. Conventional heat treating requires that parts be processed in large quantities, limiting the potential to fit into in-line cell manufacturing. All induction heating systems heat treat parts either with the part being heated in place or scanned horizontally or vertically. Induction heat treated parts include shafts, camshafts, crankshafts, push-rods, front wheel drive components, ring gears, cogs, gears of most types, connecting rods and pinions.
Induction heat treating processes include hardening, tempering, and annealing.
Typical heat-treating parameters are shown in Table 1, which may be used as a guide to initial system capabilities. Although the initial cost of induction heating equipment often is higher than that of a conventional furnace, the payback period can be short because the equipment is only on when needed, is more environmentally friendly and fits into today's manufacturing processes more readily. Fast, even heating of a billet prior to the forming operation yields the best forging. The inherently fast heating time of induction heating at the correct frequency provides that advantage. Heating for forging requires applying a low power density to the bar or billet, ensuring uniform through heating, resulting in a forging having good flow characteristics.