Heat Treatment is a process of altering the mechanical and physical properties of metal without bringing any changes to the formation of the material. It is used to increase the strength of the material. It also changes the manufacturability of the material like by restoring the ductility after the cooling treatment, improvement of the machine process and formability.It also comes in use while making glass. The performance of the material can also be enhanced by the Heat Treatment process.
The various methods involved in the heat treatment process are case hardening, precipitation strengthening, annealing, quenching and tempering. Heat Treatment is usually applied in the process of Metallurgy. In the heat treatment process, the product is chilled or heated from moderate to extreme high temperature for softening or hardening the product.
The term ‘case hardening’ refers to the case depth and hardness of the material. There are two types of this- the effective and the total case depth. The hardness equivalent of the effective case depth is HRC50 which can be verified by using a Tukon microhardness tester. This case depth approximates to 65% of the total case depth.
This approximation depends upon factors like the hardenability and chemical composition of the material. The actual depth of the case is the total case depth.In the precipitation strengthening process, the alloys are put in the freezer to prevent hardening before the product is produced or assembled.Annealing helps to make the metal soft and ductile. Quenching makes the metal hard.