Topic outline



    Metal forming is a process where materials are subjected to plastic deformation to obtain the required size, shape, and/or change the physical and chemical properties. Metal forming is divided into two groups, bulk forming, and sheet forming. Bulk forming includes forging, rolling, drawing, and extrusion, which are considered where high amount of compressive strain is imposed on the samples to improve mechanical properties. In sheet forming, usually tensile stresses are applied and forming is limited by local necking of the material. Due to the more uniform exertion of applying pressure to the workpiece by using elastic tools, parts with more uniform wall thickness and less springback and wrinkle can be generated. Forming saves material as no waste is produced. The objective is to obtain a finished surface in order to avoid expensive finishing. Metal forming processes are classified according to the effective stresses into forming under (i) compressive, (ii) a combination of tensile and compressive, (iii) tensile, (iv) bending, and (v) shearing conditions. Important processes are upsetting, wire drawing, deep drawing, extruding, stretch forming, bending, and forging. The forming process is influenced by the workpiece, the tool, the lubricant, the environment medium, and the machine. It can be described by means of yield stress, deformation size, flow conditions, anisotropy, and the flow curve.