Induction hardening is a selective heat treatment method that hardens the surface and sub-surface area of the part to the desired depth and keeps the metal core soft for toughness. Steel shafts and components made of medium carbon and alloy steel are mostly hardened using a semi or fullyautomated induction hardening machine. It is a non-contact heating process that uses high-frequency electricity to heat parts, followed by immediate quenching, see Figure 1. Since being non-contact, the heating process does not contaminate the parts, and deformation and wrapping are usually minimized. There is also no surface scale formation, which often eliminates cleanup costs.
An induction hardening system typically includes a power supply, an impedance-matching circuit, and a tank circuit, Figure 2. When the parallel set of capacitors and inductors are used in a tank circuit,the capacitor and inductor become reservoirs of electrostatic and electromagnetic energy, respectively. The high current through the coil helps to have a good energy transfer from the induction coil to the workpiece.
