Normalization covers high temperature heating and holding operations. Normalization is the heating of a steel to a temperature roughly close to its hardening temperature (usually 840 – 880 °C) and keeping it at that temperature for a period of time, followed by cooling in still air. Normalization is done to normalize this texture of material that has been damaged for any reason. Hot forged and cast materials fall into this class. There are no abnormal grains in the resulting tissue. Coarse grains crumble. It consists of ferrite and perlite in terms of structure. Normalized tissue is the most suitable tissue before hardening. For this reason, hot forged or steels are normalized before hardening. Normalization is mainly applied to plain carbon and low alloy steels. The hardness obtained as a result of this process depends on the composition and dimensions of the steel. During normalization, the difference between the cooling rate at the surface and the center of the steel is very small. In some cases, double normalization is required. This process involves initial heating of the steel to a temperature between 50 and 100 °C above normal at which the carbides can be completely dissolved in the solid solution, and a second normalization annealing to obtain a very fine grain structure. Double normalization may also sometimes be required for steels used at sub-zero temperatures. In general, it can be said that a fine-grained structure has a lower transition temperature region than a coarse-grained structure. Plain carbon or low alloy steel castings should always be normalized.


Normalization annealing is done to achieve the following purposes:

- grain size
- Obtain a homogeneous internal structure
- Carbide network at grain boundaries in supraeutectoid steels
- Improve the machinability of steels
- Improve mechanical properties
- Increasing the strength of the steel part depending on the type
- Increasing the low thermal e mechanicalness of the steel part according to the type
- To increase the hardness and strength of soft annealed steels