Practical Examples

" how industry have used these processes to design/solve problems ?" sounds too much like homework.

No the previous posts of OP does not show him to be a school going person.

But then I may be wrong .

Hot working is quite common - forging is what comes to mind in the beginning. It is done at the temperature above its recrystallisation temperature. This avoids strain hardening.

Cold working is done at lower temperature, so that a lot of residual stress may be retained as the grains slip. Strain hardning is associated with it. Cold working usually results in reduced ductility.

Certain areas where we like to convert the retained austenites to martensites we usually resort to cold working.

For cold working examples you have cold rolled steel plates (eg CRGO used in motors), Cold drawn wires (excellent YS, though reduced ductility). A number of items where you want the hardness uses the cold worked metal- rollers, dies etc.

Perhaps it's a matter of semantics, you may be right. But, "how industry have used these processes to design/solve problems" sounds like homework to me.

Cheers.