Normalizing

Normalizing:

Full anneals are time consuming and considerable energy is needed to maintain the elevated temperatures required during soaking and furnace cooling. When the maximum softness is not required and cost savings are desirable, normalizing may be specified.

In this process steel is heated to about 60⁰ C above UCT for both hypoeutectoid and hypereutectoid steels and held at this temperature to produce uniform austenite, and then removed from the furnace and allowed to cool in still air. The result structure and properties depend on the subsequent cooling rate. Although wide variations are possible depending upon the size and geometry of the metal, fine pearlite with excess ferrite or cementite is generally produced. 

                  One should note a key difference between full annealing and normalizing. In full annealing furnace imposes identical cooling conditions at all locations within the metal, which produces identical properties. With normalizing cooling will be different at different locations. When subsequent processing involves a substantial amount of machining that may be automated, the added cost of full anneal may be justified, since it produces a product with uniform machinability at all locations.