The use of impact force or pressure to make the metal in the iron or forging die deformation, so as to obtain the desired shape and size of the forging, this kind of process is called forging. Forging is one of the important forming methods of metal parts, which can ensure that metal parts have better mechanical properties to meet the requirements of use.
The forging method is characterized in that it includes forging hole, inserting wax strip, molding molding and thermalization process. The forging hole extraction process is to draw a solid rod into a hollow pipe without joint; The wax strip placement process is to insert the wax strip corresponding to the inner diameter of the hollow pipe fitting into the interior of the hollow pipe fitting; The molding process is to place the hollow pipe fitting with wax strip between the upper die and the lower die. The mold holes of the upper die and the lower die are respectively provided with corresponding concave and convex shapes. When the upper die and the lower die are pressed, reinforcing ribs can be formed on the periphery of the pipe fitting. The thermalization process will be molded by moulding.
Forging process of large forgings:
Large forging usually refers to the use of more than 1000kN hydraulic press or more than 50kN forging hammer, forging steel ingot more than 10T into a variety of heavy machinery forgings. Such as power station equipment impeller, rotor, guard ring and high pressure vessel, large crankshaft, rolling mill roll, etc. These forgings are key parts of heavy machinery, requiring high mechanical properties and reliable quality. But the production batch is generally not large, the shape is not too complex. Therefore, in the production process of heavy forgings, ensuring the quality of forgings often becomes the primary problem of making technology.
Ingot is used as blank for large forgings. The greater the weight and size of the ingot, the more serious the defect of internal structure. In order to ensure the quality of the forgings, the forging process should try to fully eliminate these defects in the processing process, and then forge into shape, size and performance to meet the requirements of the forgings. Therefore, the forging and pressing processing of large forgings has the dual role of blank forging and forming forging.
China's heavy machinery industry regulations, any free forgings that need more than 1000T forging hydraulic press production can be called large forgings. According to the forging capacity of white forging hydraulic press, roughly equivalent to; Shaft forgings with single weight above 5T and disc forgings with single weight above 32T.
Large forgings are necessary for the development of national economy, national defense industry and modern science. The production capacity and technical level of the main basic components in the device are one of the main indicators to measure the development level of heavy industry and self-sufficiency of major and key technology and equipment of a country.
Large forgings are mainly used in the following aspects:
1. Steel rolling equipment work roll, support roll and large transmission parts, etc.
2. Forging equipment module, hammer rod, hammer head, piston, column, etc.
3. Large transmission parts of mining equipment and large lifting device parts.
4. Thermal power generation equipment turbine and generator rotor, impeller, guard ring, large tube plate, etc.
5. Hydraulic power generation equipment turbine shaft, spindle, mirror plate, pressure forming large blade, etc.
6. Nuclear power generation equipment reactor pressure shell, evaporator shell, regulator shell. Turbine and generator rotors
7. Large cylinder, head and tube plate in petroleum and chemical equipment, petroleum hydrogenation reactor and ammonia synthesis tower.
8. Large crank shaft, intermediate shaft, rudder rod, etc., in shipbuilding industry.
9. Military products manufacture large gun barrel aviation turbine disc. High pressure cylinder, etc.
10. Key components in large-scale scientific research equipment.