Forging is under the external force to make the metal material plastic deformation, so as to obtain a certain shape and size of blanks or parts of the Jadin method, forging is the general term of forging and stamping, they belong to the part of the pressure processing.
Forging can be divided into forging and die forging two ways, the forging can also be divided into manual forging and machine forging two types. The materials used for forging should have good plasticity and small deformation resistance, so as to produce large plastic deformation without being destroyed during forging. In the commonly used metal materials, the forging material has low-carbon steel, medium carbon steels, low alloy steel, pure metal as well as has the good plasticity aluminum, the copper and so on non-ferrous metals, is subjected to the big force or has the special performance request important alloy steel parts; Cast iron, whether at room temperature or heating state, its plasticity is very poor, can not forge.
In production, different components of the steel should be stored separately, in order to prevent the use of wrong. Stamping more to sheet metal materials as raw materials, blanking down into the required stamping parts.
Stamping parts with high strength, rigidity, light structure and other advantages, in automobiles, tractors, aviation, instrumentation and daily necessities such as x industry occupies a very important position.
Influence of forging on mechanical properties of parts After forging the metal material, its internal defects (such as crack, loose, etc.) can be compacted under the action of forging force and form fine grains. As a result, forgings are compact and mechanical properties (especially tensile strength and impact toughness) are significantly higher than those of similar materials. Some important parts of the machine (other than the heavy load and impact loading) of the blanks, usually with the forging method of production, so that the part of the work of the normal stress and streamline direction, the direction of shear stress perpendicular to the streamline direction, as pavilion 4-1 shows. When using a round bar to make a bolt by turning method, the fiber of the head and the rod is not coherent and cut, and the head bears the cutting force in line with the direction of the metal streamline, so the quality is not high.
When the bolts are manufactured by local upsetting method in forging, the fibers are not cut off and have better fiber direction, so the quality is high. Some parts, in order to ensure the fiber direction and force direction consistent, should be used to maintain the fiber direction of the continuous deformation process, so that the distribution of the forging streamline and parts of the shape of the wheel corridor to meet without being cut off, such as the hook using forging bending process, the use of twist drill bits. The crankshaft is widely used as "the whole fiber crankshaft forging method" to improve the mechanical properties and prolong the service life.