The life of the molds in which tool steels are used varies depending on many factors; These include the chemical composition of the mold steel, the production process of the steel, the size and design of the mold, mold making techniques, production conditions, mold maintenance and heat treatment. The metallurgical and mechanical properties of tool steels are critically dependent on heat treatment. Although most Tool Steels have high hardenability and can be air hardened; It is known that the improvement in mechanical properties can be increased by increasing the cooling rate. In addition to hardness; These processes also affect the toughness and temper resistance of the material.

Optimization of material properties is a critical point in the mold industry, for example, in regions where extreme temperature cycles and cracking on the working surface of the mold are the most important factors. Also; It has been observed that the temper resistance of the material is largely dependent on the heat treatment. It is not possible to achieve the expected performance in tool steels by using only quality steel. As well as the steel quality, the effect of heat treatment and microstructures obtained after heat treatment on the mechanical and thermal properties of a Tool Steel is extremely large. It is possible to change properties such as high temperature resistance, toughness and thermal fatigue resistance positively or negatively by austenitization, cooling and tempering processes. Stress relieving annealing is absolutely applied to complex shaped and different cross-sectioned tools and molds to prevent contraction and warping that may occur during quenching. This process is done after the rough mechanical work and before the fine mechanical work.