Forging is a process involving the shaping of metal using localized compression 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 (type of cold working). warm forging or hot forging (type of working) for the latter two the metal is usually heated in a forge. Forged parts can range in weight from less than a kilogram to hundreds of metric tons. Forged parts are widely used in mechanisms and machines whenever a component requires high strength. Forging usually requires processing (machining) to achieve a finished part.