Forging is a manufacturing process involving the shaping of metal using localized compressive forces. The blows are delivered with a hammer (often a power hammer) or a die. Forging is often classified according to the temperature at which it is performed: cold forging (a type of cold working), warm forging, or hot forging (a type of hot working). For the latter two, the metal is heated, usually in a forge. Forged parts can range in weight from less than a kilogram to hundreds of metric tons.
Processes : There are many different kinds of forging processes available, however they can be grouped into three main classes:
• Drawn out: length increases, cross-section decreases
• Upset: length decreases, cross-section increases
• Squeezed in closed compression dies: produces multidirectional flow