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Heat Treatment

 

Heat treatment is the systematic heating and cooling of a material for the purpose of altering its physical properties.  

Heat Treating of Steel 

Annealing is a general term applied to the heat treatment process of steel. The goal of annealing may be to alter the steel’s ductility, grain size, toughness, or hardness, in order to make it more suitable for a subsequent process.  

Full annealing vs. Normalizing 

When steel material is given a full annealing treatment, it is first heated in a furnace. Then the temperature in the furnace is deceased by a few degrees each hour.  

Normalizing is another kind of heat treatment. The heating phase of normalizing is similar to full annealing. However, when a material is normalized, it is left to cool at room temperature after the heating phase. Normalizing takes less time---and is therefore cheaper---but the resultant material differs from material that has undergone full annealing. 

Fully annealed material has a consistent internal structure (the interior and exterior portions are the same). Normalized material, however, has inconsistencies between the interior and the surface.  

Normalizing may be adequate---it depends on the ultimate use of the material. If the objective is simply to change the surface of the material for finishing operation, then normalizing is enough. However, if the material will be subjected to operations that require interior and exterior consistency, then full annealing might be necessary.