Metal forming is the process of manufacturing blanks and fittings by plastic deformation of the source material. This type of processing can be subjected to materials with sufficient plastic properties. For brittle alloys, such as cast iron, this method of shaping is not used because of the high probability of destruction of the part as a result of strong external influences.
The technology for the production of semi-finished products and finished products in this way involves the use of material in both cold and hot conditions. This entails significant differences in the properties of the finished product. Processing of metals by pressure will only slightly change the structure, therefore, of the physico-mechanical properties of the material, if it was initially in a hot state.
Cold forming of metal billets is used in the case of manufacturing a large batch of small high-quality parts. This is due to the fact that in such a state hardening of the material occurs, accompanied by a change in its properties. In particular, the strength characteristics of the finished product are increased.
The theory of metal forming is based on the application of the plastic properties of these materials. In particular, their ability to permanent deformation is used, in which the body retains its size and shape, even after the external load has been removed. The change in the geometric parameters of the product occurs due to static or dynamic external pressure, which causes significant stresses in the alloy, the value of which exceeds significantly the yield strength.
The following types of metal forming are distinguished:
rolling, during which the processed material is subjected to compression on special equipment by passing between the rollers, which are notified of the rotational movement ;
drawing. In this case, only long products, such as wire, bar or pipe, are shaped. The essence of this treatment is to pull the source metal through a hole of a smaller size than the diameter of the original billet, located in a special tool - die;
free forging, which involves successive changes in the shape and size of the part in the hot state as a result of successive hammer blows or pressure created by the press. This type of processing allows you to improve the structure and properties of forging;
stamping, which can be both sheet and volumetric. In both cases, the same equipment is used: a press and a stamp, however, the ratio of the size of the workpiece is different;
pressing, in which the material is extruded from a closed shape having holes.
Metal forming has several advantages, among which are:
the possibility of mechanization and automation of the manufacturing process of parts;
increased utilization of the material;
manufacturing of products of various shapes and sizes, and for some parts no further machining is required, for the rest - its volumes are significantly reduced;
increasing the productivity of the manufacturing process of various products;
improving the mechanical properties of alloys.
Metal forming is widely used in the industrial complex of our country. This method produces various body parts having complex geometry and large dimensions. If necessary, if the required dimensions, shape or surface quality were not achieved with this method of shaping, then the next step is machining. If it is necessary to increase the operational properties of the finished product, then at the final stage heat treatment is performed .