Isothermal annealing is a process that is carried out both to increase the machinability of the material and to reduce the deformations that may occur during carburising.
It gives the steel the correct and homogeneous internal structure required for machinability. It is a process for transforming steel into pearlitic structure. It is applied to parts to be precision machined and parts to be surface treated. It is used especially in machine elements that transmit power and motion, as it provides a good and homogeneous internal structure and increases the machinability ability.
This process is mostly applied in semi-finished products, parts that have different heat-affected areas such as high temperature forged, rolled or welded areas, and for the refinement of the grain structure of coarse-grained materials.