Metal forming

Processing of metals by pressure - the process of manufacturing blanks and shaped parts by plastic deformation of the starting material. This kind of processing can be subjected to materials that have 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 a strong external influence.

The technology of production of semi-finished and finished products in a similar way involves the use of material that is in both cold and hot state. This entails significant differences in the properties of the finished product. Processing of metals by pressure will only slightly change the structure, and therefore, the physical and mechanical properties of the material, if it was originally in a hot state.

Shaping of a metal blank in the cold state is used in the case of manufacturing a large batch of small high-quality parts. This is due to the fact that in this state the material hardens, 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, in which the body retains its dimensions and shape, is used, even after the external load has been removed. The change in the geometric parameters of the product is due to static or dynamic external pressure, which causes considerable stresses in the alloy, the value of which exceeds the yield point considerably.

The following types of metal forming are distinguished:

• Rolling, during which the material to be processed is crimped on special equipment by passing between the rollers, which are informed of the rotational motion ;

• drawing. In this case, only long products, such as wire, rod or pipes, are formed. The essence of this treatment is the pulling of the parent metal through a hole of smaller size than the diameter of the initial workpiece, located in a special tool - a dredge;

• Free forging, which provides for a consistent change in the shape and size of parts in the hot state as a result of successive hammer blows or pressure created by the press. This kind of processing allows to improve the structure and properties of forging;

• Stamping, which can be both sheet and volume. In both cases, the same type of equipment is used: a press and a stamp, but the ratio of the dimensions of the workpiece is different;

• Pressing, in which the material is extruded from a closed mold having openings.

Processing of metals by pressure has a number of advantages, among which we can distinguish:

• The possibility of mechanization and automation of the process of manufacturing parts;

• Increase in the utilization factor of the material;

• Manufacturing of products of various shapes and sizes, with no further machining required for individual parts, for others - its volumes are significantly reduced;

• Increase the productivity of the process of production of various products;

• Improvement of mechanical properties of alloys.

The treatment of metals by pressure 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 shaping method, the next step is machining. If it is necessary to improve the operational properties of the finished product, then the final stage is heat treatment.