WLDMF501-METAL FORMING
Introduction
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.