Forging is a manufacturing process where metal is pressed, pounded or squeezed under great pressure into high strength parts. The process is normally (but not always) performed hot by preheating the metal to a desired temperature before it is worked. 

The forging process is entirely different from the casting (or foundry) process, as metal used to make forged parts is never melted and poured as in the casting process.

Forgings are used in places where reliability and safety are critical.  Forgings are often parts that are used inside machines, automobiles, airplanes, tractors, ships, oil drilling equipment, engines etc.