Heat Treating is an operation or combination of operations involving the controlled heating and cooling of solid metals and alloys to obtain a required microstructure with resultant desired properties. Annealing is a general term applied to the heat treatment process of steel. The goal of annealing may be to alter the steel’s ductility, grain size, toughness, or hardness, in order to make it more suitable for a subsequent process. There are numerous heat treating methods including quenching, a process in which metal is heated to the point where there is a change in the microstructure, and then rapidly cooled to force an unusual microstructure change not found in slow cooling. Milling, buffing, rolling, or forging metal can create stresses in metal parts, but in an annealing process, metal is heated nearly to quenching temperature, but is slowly cooled to create a microstructure free of stress. The stress relieving process heats the part to an even lower temperature to deal with residual stress by partial annealing. Tempering, carburizing, and carbonitriding are other heat treating processes that result in changes to the toughness and hardness of a metal component.