Forging

Forging, shaping metal by hammering or pressing, usually when the work-piece is red hot (about 400°–700°C) but sometimes when it is cold. Unlike casting, forging does not alter the granular structure of the metal, and hence greater strength is possible in forged than in cast metals. The most basic method of forging is that of the blacksmith, who heats the metal in an open fire (forge) and hammers it into shape against an anvil. Today, metals are forged between two dies, usually impressed with the desired shape. Techniques include drop forging, where the workpiece is held on the lower, stationary die, the other being held by a massive ram that is allowed to fall; press forging, where the dies are pressed together; and impact forging, where the dies are rammed horizontally together, the workpiece between.