Introduction to Bulk-Forming Processes

METALWORKING consists of deformation processes in which a metal billet or blank is shaped by tools or dies. The design and control of such processes depend on the characteristics of the workpiece material, the conditions at the tool/workpiece interface, the mechanics of plastic deformation (metal flow), the equipment used, and the finished-product requirements. These factors influence the selection of tool geometry and material as well as processing conditions (for example, workpiece and die temperatures and lubrication). Because of the complexity of many metalworking operations, models of various types, such as analytical, physical, or numerical models, are often relied upon to design such processes. This Volume presents the state-of-the-art in bulk-metalworking processes. A companion volume (ASM Handbook, Volume 14B, Metalworking: Sheet Forming) describes the state-ofthe-art in sheet-forming processes. Various major sections of this Volume deal with descriptions of specific processes, selection of equipment and die materials, forming practice for specific alloys, and various aspects of process design and control. This article provides a brief historical perspective, a classification of metalworking processes and equipment, and a summary of some of themore recent developments in the field.