Purposes and methods Of Heat Treatment

Heat Treatment refers to a combination of heating and cooling of a metal or alloy in the solid state for the purpose of obtaining desired properties. Changes in properties result from micro structural changes in the material produced by heat treatment operations.

However, these serve one or more of the following purposes :

1. Improve machinability.

2. Relieve Internal Stresses.

3. Improve mechanical properties such as ductility, strength, hardness, toughness etc.

4. Change the grain size.

5. Increase resistance to heat and corrosion.

6. Modify electrical and magnetic properties.

7. Change the chemical composition.

8. Remove gases.

The aforesaid purposes of heat treatment may be served by one or more of the following processes of heat treatment :

1. Annealing.

2. Normalizing.

3. Hardening.

4. Tempering.

5. Case Hardening :

a.) Carburizing.

b.) Cyaniding.

c.) Nitriding.

6. Surface Hardening :

a) Induction Hardening.

b) Flame Hardening.

7. Diffusion Coatings.

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