Heat treatment consists of raising the austenitizing temperature followed by quenching (hardening) that is appropriate for the material and the required properties. Depending on the composition of the steel, the austenitizing temperatures range between 800 °C and 900 °C. Hardening is followed by a further heat treatment process known as tempering, which takes place in separate systems. If tempering is carried out at over 350 °C, this is referred to as heat treatment rather than hardening and tempering. The goal of heat treatment is to create a homogeneous structure with increased strength and high ductility.
If the mechanical properties of a heat treated component are not sufficient to meet the requirements placed on the component, a second, typically thermochemical, heat treatment such as case hardening or nitriding follows between the mechanical pre-processing and the finishing process.