Induction Hardening Video

The hardening process consists of heating the components above the critical temperature, holding at this temperature for one hour per inch of thickness cooling at a rate fast enough to allow the material to transform to a much harder, stronger structure, and then tempering if necessary.

Hardening involves controlled heating to a critical temperature dictated by the type of steel (in the range 760-1300 C) followed by controlled cooling. Dependent on the type of material, appropriate cooling rates vary from very fast (water quench) to very slow (air cool).

Hardening steel is a common process used to toughen many engineering items, as well as everyday products.

There are three main techniques to harden steel:
Case hardening – involves adding carbon through heating to strengthen the outer layer, ideal for cooking utensils and hard-wearing parts, that don’t require ductile properties.
Through hardening – involves heating and rapidly cooling the steel to strengthen the entire structure, ideal for fittings and hand tools
Flame hardening – involves heating the outer layer to create a tough outer layer of 1-10mm depth, ideal for hard-wearing, flat surfaced items and sheets such as knives and saws.