Question

what happens if when a blacksmith hammers a red hot piece of iron

Answer 1

The process of hammering a hot piece of iron by a blacksmith or any other person is known as forging.

The hammering changes the arrangement of the iron crystals. If the iron is very hot then the strain developed by the hammering of the iron crystals is known as re-crystallization.

Basically, the iron will change its shape and will be taking the form of thin sheets. This property of iron is known as malleability.