The steel part is heated under protective gas up to the austenite phase temperature (mostly 810-900 OC) and at this temperature it is hardened by being kept in oil for a certain period of time according to the thickness of the part.

At the end of the hardening process, the extent to which the hardness progresses from the surface of a piece to its core depends on the hardenability of the steel, that is, the chemical composition of the steel and the grain structure. Since the martensitic structure obtained after hardening is extremely hard and brittle, tempering is applied to give a sufficient structure to the material, to remove the stresses and to obtain the necessary surface hardness. It is applied at varying temperatures (usually 150-650°C) depending on the desired hardness.

Since there is no waiting period in the gas atmosphere controlled kontiniu furnace, the risk of cracking of the products ceases to exist. It offers a great advantage over other heat treatment methods. Homogeneous hardness distribution is obtained in the pieces when the pieces do not stack too much and cool individually, not in mass.