Normalising

Normalising is the process of raising the temperature to over 60 ºC (140 ºF), above line A3 or line ACM fully into the Austenite range. It is held at this temperature to fully convert the structure into Austenite, and then removed from the furnace and cooled at room temperature under natural convection. This results in a grain structure of fine Pearlite with excess of Ferrite or Cementite. The resulting material is soft; the degree of softness depends on the actual ambient conditions of cooling.

Main objectives of normalisation annealing:

Shrink grain

Obtaining a homogeneous structure

Distribute the carbide network at grain boundaries of the above eutectoid steels

Improve the processing properties of steels

Improve mechanical properties

Increase the hardness and strength of steels