Martensitic or quench hardening, neutral hardening is a heat treatment used to achieve high hardness / strength on steel. It consists of austenitising, quenching and tempering, in order to retain a tempered martensite or bainite structure.teel can be treated by intense heat to give it different properties of hardness and softness. This depends on the amount of carbon in the steel (only high carbon steel can be hardened and tempered). Tempering is a low temperature (150°C to 650°C) heat treatment intended to remove the stresses and brittleness caused by quenching and to develop the required mechanical properties.