Engineering Question:

Heat treatment can be defined as a combination of processes or operations in which the heating and cooling of a metal or alloy is done in order to obtain desirable characteristics without changing the compositions. Some of the motives or purpose of heat treatment are as follows:
☛ In order to improve the hardness of metals.
☛ For the softening of the metal.
☛ In order to improve the mach-inability of the metal.
☛ To change the grain size.
☛ To provide better resistance to heat, corrosion, wear etc.