Metal billets (not including the board) the imposition of external force to produce plastic deformation, change the size, shape and improve performance for the manufacture of mechanical parts, parts, tools or methods of forming blanks.

The catogories and specialty of forging:

When the temperature exceeds 300-400 ℃ (steel blue brittle region), to 700-800 ℃, the deformation resistance will be drastically reduced, deformation can also be significantly improved. According to the different regions of the forging temperature, forging quality and forging process for the different requirements can be divided into cold, warm forging, hot forging three molding temperature region. Originally this temperature there is no strict division of the region boundaries, generally speaking, in a recrystallization temperature region of the forging is called hot forging without heating at room temperature is called cold forging.

At low temperature, forging, the forging of the size changed little. The following forging at 700 ℃, less oxide formation, and free of surface decarburization phenomenon. Therefore, as long as the deformation energy in the context of forming, cold forging easy to get a good dimensional accuracy and surface finish. As long as good control of temperature and lubrication cooling, 700 ℃ temperature below can also get very good precision forging. Hot forging, due to deformation energy and deformation resistance are small, complex shapes can be forged large forgings. To obtain high dimensional accuracy of forgings, can be used within the temperature 900-1000 ℃ hot forging process. Also, pay attention to improve the forging of the work environment. Forging Die Life (Hot 2-5 1000, 1-2 million warm forging, cold forging 2-5 million) and other temperature field is shorter than the forging, but it’s freedom, low cost .

Blank when the cold deformation and work hardening, forging die to withstand high loads, therefore, need to use high-strength forging die and to prevent wear and bond with the hard lubricating film treatment. In addition, to prevent the billet crack, intermediate annealing when necessary to ensure the needs of deformation. In order to maintain good lubrication can be carried out on the blank phosphate treatment. The use of bar and wire rod continuous process, the present section can not be lubricated treatment, is studying the possibility of using phosphate lubrication

According to the movement of blank form, forging can be divided into free forging, upsetting, extrusion, forging, closed die forging, closed upsetting. Closed die forging and closed upsetting the absence of flash, material utilization will be high. Road with a process or processes may be completed several complex forgings finishing. In the absence of flash, forging the force area is reduced, the required load is reduced. However, be careful not to be restricted entirely blank, this should strictly control the volume of blanks, control the relative position of forging die and forging measure, efforts to reduce the wear of forging dies. Forging die according to the sport, and forging can be divided into Orbital, Pendulum spiral forging, roll forging, wedge rolling, ring rolling and cross rolling etc.. Rotary forging, rotary forging and ring rolling pendulum can also be used precision forging. In order to improve material utilization, roll forging and rolling thin material can be used as working procedure before processing. As with the free rotation of forging forging is partial forming, it has the advantage of size in comparison with the forging, forging force can be achieved under less form. Including the freedom of this forging method, including forging, machining material from the mold surface near the free surface to expand, it is difficult to ensure accuracy, so the movement direction of the forging die and rotary forging process controlled by computer, you can use lower The forging force was complicated shape, high precision products. For example, production variety, size large turbine blade forging.

Die forging equipment, exercise is inconsistent with freedom, according to the characteristics under the four-point deformation limit, forging equipment can be divided into the following four ways:

• restrictions on the form of forging force: direct drive hydraulic ram hydraulic press.

• quasi-stroke limit means: hydraulic drive connecting rod hydraulic machine.

• stroke limit by: crank, connecting rod and the wedge bodies driven mechanical press slide.

• energy restriction method: use of helical screw mechanism and friction presses.

In order to obtain high accuracy should be noted that under the dead point to prevent overload, control speed and mold position. Because these will be on forging tolerances, the shape precision and impact forging die life. In addition, in order to maintain accuracy, adjust the slider guide clearance should also be noted, to ensure rigidity, adjustment benefits under the dead and use of gear and other measures.

In addition, there is under way slider Slider vertical and horizontal movement (for slender parts forging, cooling and lubrication of high speed production of parts, forging) way of points, use of compensation devices can increase the other direction of movement. The different ways, forging the necessary strength, processes, materials, utilization, yield, size tolerances and lubrication cooling are not the same, these factors also affect the level of automation factors.