We use induction hardening as a surface hardening technique
Induction hardening creates a very hard surface layer on low- or high-strength workpieces. Usually, the workpiece is hardened selectively in a specific area, using an induction coil to heat the surface to the hardening temperature.
A special quenching medium is then sprayed onto the workpiece, producing a martensitic structure in the hardened layer. Induction hardening can be performed on steels with a minimum carbon content of around 0.3 %. Some steels with a lower carbon content can also be induction-hardened.