INTRODUCTIONHeat treatment processes are able to change the properties and conditions of materials subjected to such treatment. Heat treatment can improve toughness, machinability, and wear resistance; increase ductility and hardness; remove residual stresses and refine grain structure. There are several different processes of heat treatment, such as annealing, normalizing, and tempering.Annealing treatments are used to soften a material. This process involves heating to a specific temperature and then slowly cooling. The treatment is usually done after cold working or before machining. There is also another form of annealing called spherodizing, which is used in higher carbon steels. Spherodizing makes the steel softer and easier to machine by creating a microstructure of Fe3C spheroids in a ferrite matrix.When cooling is done at a faster rate, it is called normalizing. Normalizing is performed in the air instead of the furnace. Another difference between annealing and normalizing is the mixture contents. In normalized steels, there will be finer pearlite along with ferrite and cementite. These are diffusion transformations requiring time. Diffusionless transformations in steels have the possibility to produce meta-stable phases such as martensite. This phase is caused by the rapid cooling from quenching the material. The martensite is very hard and very brittle, which makes for good wear resistance. However, impact resistance will be very poor. The carbon content of the material will dictate the quantity of martensite produced; the higher the carbon content, the higher the martensite produced. To reduce the brittleness while maintaining the materials strength and hardness, tempering must be used.