Annealing And Heat Treatment by hkksew3563rd

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									There are several procedures of heat treatment for steel and other materials, annealing
being one of them. Different industries have different mechanization requirement for
steel and other materials, and the different processes of heat treatment are a way to
impart characteristics like optimal hardness and adequate malleability to the materials.
In the annealing process steel is heated to a specific temperature in the austenite area
and then cooled gradually. The procedure is used to gain rough equilibrium state in
materials, for instance steel is subjected to the process to get a ferrite-pearlite
microstructure. There are several advantages of the process, which are also the reason
why this process is so widely used across the industry. Improves and enhances
machinability of steel Enhances ductility of the material The material is softened
through the process The material becomes stronger The molecular structure of the
element becomes more homogenous and hence the material becomes more
industrially usable. The grain structure of the element is refined and improved. The
material becomes ready for further heat treatment through other processes.
There are several derivatives of the annealing process depending on specific thermal
cycles. And, depending on the materials that need heat treatment and the result
specifications, the processes may differ. For the treatment of steel it is heated through
an annealing furnace or sometimes even through other sources of heat. The material is
often kept in touch with carbon for it to be carburized in the process and is heated to a
particular temperature, depending on its carbon content. The general rule of thumb is
that the higher the carbon content of the steel the lower the temperature required. The
temperature that is normally required for a successful treatment ranges from 760 to
910 degrees Celsius.

Heating steel to these temperatures changes the internal molecular structure of the
element. Before the process is undertaken, steel is usually pearlite, which means it
normally has overlapping layers of alpha-ferrite and cementite. Alpha-ferrite usually
constitutes 88% of steel and is dissolved through this process forming austenite
crystals.

It is advisable to let the steel cool very slowly and gradually during the process.
Particularly because it is during the cooling process that the austenite gradually
transforms back into pearlite crystals, leaving significant changes to the composition
of the element. After a successful treatment procedure, steel contains the large ferrite
molecules interspersed between the pearlite crystals. The slower the cooling process
the better the formation of this structure. Again, heating the steel to temperatures that
are beyond the specified limit may cause the steel to be brittle due to the formation of
large austenite crystals. To conduct annealing or any other heat treatment process
successfully, hence, heating to the right temperature and then cooling at a specified
rate is very important.

There are several processes of annealing like bright annealing, process annealing,
recrystallization annealing, sub critical annealing, spheroid annealing, isothermal
annealing, full annealing, etc. Each process is instrumental in producing different
varieties of steel that can be used for different industry requirements. For instance,
spheroid annealing is used to produce alloys of steel, and recrystallization annealing is
done to impart a distinguishing grain structure to the element.
 Annealing is popularly used heat treatment process in the industry to impart strength
and flexibility to industrial metals like steel. Log on to www.heat-treat.co.uk to find
professional annealing and other heat treatment services at reasonable prices.

								
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