The metal blank (excluding plate) is used to produce plastic deformation, change the size, shape and improve the performance of the metal material.

Types and characteristics of forging

When the temperature is over 300 (-400), the deformation resistance will be reduced sharply, and the deformation can be greatly improved when the temperature exceeds 700. According to the different temperature regions of forging, for forging quality and forging process requirements of different, can be divided into cold forging, warm forging, hot forging three forming temperature region. There is no strict boundaries of the division of this temperature region, generally speaking, in the region of the temperature of the forging is called hot forging, not heated at room temperature of the forging is called cold forging.

In low temperature, the size of the forging is very small. In 700 DEG forging, oxide formation, and surface decarburization. Therefore, as long as the deformation can be in the range of the forming, cold forging easy to get good dimensional accuracy and surface finish. As long as the control of temperature and lubrication cooling, the following 700 degrees Celsius temperature can also get a good accuracy. In the hot forging, the forging of complex shapes can be forged by the deformation energy and the deformation resistance. Forging with high dimensional accuracy can be obtained in the temperature range of 900 for -1000 and the heat forging process. In addition, pay attention to improve the working environment of hot forging. The forging die life (hot forging 2-5 1000, 1-2 million warm forging, cold forging 2-5 million) compared with other temperature field of forging is shorter, but its degree of freedom, low cost.

Blank in the cold forging to produce deformation and hardening, making the forging die under high load. Therefore, it is necessary to use high strength die and used to prevent the adhesion wear and hard lubricating film processing method. In addition, in order to prevent the billet cracks, intermediate annealing is needed to ensure the required deformation capacity. In order to maintain a good lubrication condition, the material can be used for phosphating treatment. The use of bar and wire rod continuous process, at present section can not be lubricated, are studying the use of phosphatizing lubrication method.

According to the movement of the blank, forging can be divided into free forging, upsetting, extrusion, forging, closed die forging, closed upsetting. Closed die forging and closed upsetting because no flash, high material utilization rate. With a process or a few steps may complete the fine processing of complex forgings. As a result of the absence of the flying edge, the stress area of the forging is reduced, and the required load is also reduced. But should be careful not to be restricted completely blank, therefore to strictly control the blank size, relative position control of forging die and forging of were measured efforts to reduce die wear.

According to the motion mode of forging die, forging can be divided into rotary pendulum, rotary forging, roll forging, cross wedge rolling, ring rolling and cross rolling etc.. Rotary forging, rotary forging and rolling pendulum ring forging process is also available. In order to improve the utilization ratio of material, roll forging and cross rolling can be used as the front working procedure of slender material. The same as the free forging is also a part of the rotary forging, it has the advantage of the same size, compared with the forging force can also be achieved in the case of small forging. Including free forging, the forging, machining material from the mold surface near to a free surface expansion. Therefore, it is difficult to guarantee the accuracy, so will die of the direction of motion and rotary forging process by computer control, can lower the forging force obtained products with complex shape and high precision. For example, the production of varieties, large size of the turbine blades, etc..

Forging equipment of mold and degrees of freedom is not consistent, according to the lower dead point deformation limit characteristics and forging equipment can is divided into the following four types:

Limit of the form of the forging force: the hydraulic pressure of the oil press directly drives the slider.

Quasi - stroke limit mode: oil pressure driven crank connecting rod mechanism.

The stroke limit mode: the mechanical press of the crank, connecting rod and wedge mechanism.

Energy limitation: the use of screw and friction press.

In order to obtain high accuracy should be taken to prevent the bottom dead center overload, control the speed and position of die. Because these will have an impact on the forging tolerances, shape accuracy and die life. In addition, in order to maintain the accuracy should also note slider guide rail gap adjustment, ensure the stiffness, adjust the bottom dead center and utilization subsidies transmission device and other measures.

In addition, according to the movement of the slider, the slider is vertical and horizontal motion (for the elongated parts of the forging, lubrication cooling and high speed production of parts forging), the use of the compensation device can increase the other direction of movement. The method is different from the method of forging force, working procedure, the use of the material, the output, the dimension tolerance and the lubrication cooling way are not the same, these factors also affect the level of automation.