'Recognizing the need is the primary condition for design.'
The heat treatment of metals always results in incresed or changed properties of the metals that are heat treated.
Below are numerious resources to help you learn about the different methods of heat treatment as well as when and why they may need to be applied.
Common heat treatment process are:
Hardening, Annealing, Quenching and Tempering
This presentation covers the basic facts concerning heat treatment of metals, it has some informative videos in the content.
This presentation covers, cold and hot forming of extrusions and wires as well as air hammer die press work.