Definition - What does Induction Hardening mean?
Induction hardening is a heat-treating process used to increase the hardness or wear resistance of a material. Induction hardening heats a material using a form of induction heating to a specific temperature. Once the temperature is reached, it is rapidly cooled by a quenching media. This rapid cooling forms a material microstructure that is hard and strong.
Induction hardening has several benefits over other hardening methods. It is easier to control because it is an electrical process rather than a combustion process. Another benefit is that it begins heating the surface of the material, rather than the core. This makes induction hardening an excellent option for case hardening. Since precise controls can be used in induction hardening, a uniform case hardened surface can be created. The depth of the hardened material can also be readily controlled.
Corrosionpedia explains Induction Hardening
Induction hardening relies largely on the energy transferred to a material by induction heating. Induction heating involves placing a copper coil around a material and running an alternating current through it. The shifting magnetic fields caused by an alternating current will cause the surface of the material to rise in temperature. It works especially well if the material has iron in its composition.
The induction heating continues until the desired depth of heating is reached. The material is then cooled rapidly with a quenching media. This media can be air, water, brine, or oil, to name some of the possibilities. Once cooled, the portion of the material that was heated above the required temperature and cooled quickly enough will have increased hardness and strength, assuming the material is responsive to quench hardening.