Hardening is a process of increasing the hardness and mechanical strength of steel. Steel is heated to a temperature slightly higher than the upper critical (between 850-900ºC) and then cooled more or less quickly (depending on the characteristics of steel) in a quenching medium such as oil, air, water, water mixed with soluble polymers, etc.
Normally steels are used in induction hardening contain from 0.3% to 0.7% carbon (hypoeutectic steels).
Case or surface hardening is the process of hardening the surface of a metal object and thus forming a thin layer of harder metal at the surface.
For iron or steel with low carbon content, which has poor to no hardenability of its own, the case hardening process involves infusing additional carbon into the case. Case hardening is usually done after the part has been formed into its final shape, but can also be done to increase the hardening element content of bars to be used in a pattern welding or similar process.
Because hardened metal is usually more brittle than softer metal, through-hardening (that is, hardening the metal uniformly throughout the piece) is not always a suitable choice for applications where the metal part is subject to certain kinds of stress.
|600 - 4000 mm
|100 - 250 mm/sec
|5 - 1000 kW
|3 - 400 kHz