What are the Stages of heat treatment process

All heat treatment processes comprises 3-main steps:

(i)  Heating of metal/alloy to the predetermined (definite) temperature.

(ii) Holding (or soaking) of the metal at that temperature for a sufficient period to allow necessary changes (for example Austenitizing) to occur i.e. structure becomes uniform throughout the section.

(iii) Cooling at a predetermined rate necessary to attain desired properties associated with changes in nature, form, size and distribution of.