Forging is a manufacturing process involving the shaping of metal using localized compressive forces. Forging is often classified according to the temperature at which it is performed: cold forging or hot forging. Customized Forgings can range in weight from less than a kilogram to hundreds of metric tons.
Forging can produce a piece that is stronger and superior than an equivalent cast or machined part. It can also achieve a lower total cost in the overall product’s life cycle than casting or fabrication.
- Closed die / Impression hot forging: In closed/impression-die forging, the metal is placed in a die resembling a mold. The hammer is then force dropped on the workpiece, causing the metal to flow and fill the die cavities. Depending on the size and complexity of the part, the hammer may be force dropped multiple times in quick succession.
- Open die hot forging: In open-die forging, a hammer strikes and deforms the workpiece. In open-die forging the dies do not enclose the workpiece, allowing it to flow except where contacted by the dies. It is the skill of the operator that orients and positions the workpiece to get the desired shape.
- Roll forging: Roll forging is a process where round or flat bar stock is reduced in thickness and increased in length. Roll forging is performed using two cylindrical or semi-cylindrical rolls, each containing one or more shaped grooves. A heated bar is inserted into the rolls which gets a progressive shaped as it is rolled through the machine.