Heat treatment is the process used to modify the mechanical and physical properties of metal without altering the materials formation. It usually increased the material’s strength. It is also used to modify the objective of some material aspect manufacturability like, restoring ductility after the cooling treatment, improving the machine process and to improve its formability. It is also somehow used to manufacture certain materials like glass. It also improves the materials performance. Metallurgical process is where usually the heat treatment is being applied. To attain the preferred outcome such as softening and hardening of the product, heat treatment process includes the chilling and heating of such product from moderate to extreme high temperature.

The heat treatment processing methods involves case hardening, precipitation strengthening, annealing, quenching and tempering. Case hardening is specifically meant the case depth and hardness of the material. This has two classifications, the effective and the total case depth. HRC50 is the hardness equivalent of the effective case depth which is can be test using Tukon microhardness tester. The value of this case depth is approximately 65% of the value of total case depth. But the approximation can be affected by hardenability and chemical composition of the material. The total case depth is the correct depth of the case.

Precipitation strengthening used to either some precipitation hardening metals like alloys from hardening, since some metals are easier to assemble if it is soft. Alloys are put in the freezer to avoid hardening prior to the production or assembly of the product. To reduce the stress applied to the material, annealing method is being used. This method usually produces a ductile and soft metal. Quenching is done to harden a metal. The metal is usually heated and the cooled quickly. Cooling process is usually done by exerting forced gas or air.