Normalizing is the process in which a part is heated above its critical temperature, held, and then air-cooled to form a more homogenous structure and refine the grain size. This removes impurities in the material and improves the component’s ductility and toughness. Normalization can also improve a material’s machinability, making it easier to shape.
Normalizing can occasionally be substituted for conventional hardening if there is risk of cracking, distortion, or excessive dimensional changes in the material. This depends on the mechanical properties required of the component and the metal being treated.
Normalizing is similar to annealing treatment, including a heating and cooling cycle, but they should not be confused with one another. Annealing’s cooling cycle is controlled within a furnace, while the cooling part of Normalizing is done within a room temperature environment.
Materials suitable for normalizing
- Iron Alloys
- Nickel Alloys
- Various Steels
TMT’s Equipment and Variations of normalizing
Normalizing can be performed in an endothermic or air atmosphere. An endothermic process will reduce the amount of scaling, but some scaling will remain present due to the cooling part of the cycle. Induction heating can also be used to limit normalization to certain areas of a part as needed.
- Normalizing is often performed after forging or casting to eliminate forming stresses, reduce segregation, and refine the grain size. It also is done before other heat-treating options as well as normalizing improves the mechanical properties of the component.
- Normalizing is used in situations where strength levels obtained by quench and tempering are not necessary, but superior strength to the annealed or as rolled condition is needed.
- Normalizing can improve dimensional stability of the workpiece or component in subsequent machining operations.
- AMS 2759/1, AMS-H-6875
- ASTM A106, A350, A668
What To Consider When Specifying
- Processing Atmosphere
- Hardness range (if required)
- Spec (if required)