Manufacturing Properties of Metals

Methods of plastic deformation are used extensively to force metal into a required shape. The processes used are diverse in scale, varying from forging and rolling of ingots weighing several tons to drawing of wire less than 0·025 mm (0·001 in) in diameter. Most large-scale deformation processes are performed hot, so that a minimum of force is needed and the consequent recrystallization refines the metallic structure. Cold working is used when smooth surface finish and high dimensional accuracy are required. Although a growing number of components is manufactured completely from a series of deformation processes, metal forming is primarily used to produce such material as bar and sheet which is subsequently machined or pressed into its final shape. A chart showing the major metal-forming processes can be seen in Fig. 2.1.