Forging category

According to the forming mechanism, forging can be divided into free forging, die forging, grinding ring and special forging

Three Gorges ship lift nut billet

1, free forging. It refers to the processing method of forging parts with simple universal tools, or directly applying external force to the blank between the upper and lower anvils of forging equipment, so that the blank can be deformed and the required geometric shape and internal quality can be obtained. The forging produced by free forging method is called free forging. Free forging is based on the production of small number of forgings, forging hammer, hydraulic press and other forging equipment to form the blank processing, obtain qualified forgings. The basic processes of free forging include upsetting, drawing, punching, cutting, bending, twisting, dislocation and forging. Free forging is all hot forging. [2]

2, die forging. Die forging is divided into open die forging and closed die forging. The metal blank is deformed under pressure in the forging die chamber of a certain shape to obtain the forging. Die forging is generally used to produce small weight and large batch parts. Die forging can be divided into hot die forging, warm forging and cold forging. Warm forging and cold forging are the future development direction of die forging and represent the level of forging technology. [3]

According to the material, die forging can also be divided into black metal die forging, non-ferrous metal die forging and powder products forming. As the name implies, is that the materials are carbon steel and other ferrous metals, copper and aluminum and other non-ferrous metals and powder metallurgy materials.

Extrusion should be attributed to die forging, can be divided into heavy metal extrusion and light metal extrusion.

Yankuang Group 150MN extrusion production line, the world's largest

Yankuang Group 150MN extrusion production line, the world's largest

Closed die forging and closed upsetting forging are two advanced techniques of die forging. Because there is no flying edge, the material utilization rate is high. It is possible to finish complex forgings with one or more steps. Because there is no flying edge, the forgings force area is reduced, the required load is reduced. However, it should be noted that the blank can not be completely limited, so it is necessary to strictly control the volume of the blank, control the relative position of the forging die and measure the forgings, and try to reduce the wear of the forging die. [3]

3, grinding ring. Grinding ring refers to the production of ring parts of different diameters through special equipment grinding ring machine, also used to produce car wheel hub, train wheels and other wheel parts. [4]

4, special forging. Special forging includes roll forging, cross wedge rolling, radial forging, liquid die forging and other forging methods, which are more suitable for the production of some special shape parts. For example, roll forging can be used as an effective preforming process to greatly reduce the subsequent forming pressure; Cross wedge rolling can produce steel balls, drive shafts and other parts; Radial forging can produce large gun barrel, step shaft and other forgings. [4]

die

According to the motion mode of forging die, forging can be divided into swing forging, swing forging, roll forging, cross wedge rolling, ring rolling and cross rolling. Rotary forging, rotary forging and rotary forging

China's first 400MN (40,000 tons) heavy aviation die forging hydraulic press

China's first 400MN (40,000 tons) heavy aviation die forging hydraulic press

Rings can also be machined by fine forging. In order to improve the utilization rate of materials, roll forging and cross rolling can be used as the prior process of slender materials. Rotary forging, like free forging, is also partially formed. Its advantage is that compared with the forging size, the forging force can also be formed under the condition of small. Including free forging, the way of forging and processing the materials from the mold surface near to the free surface extension, therefore, it is difficult to guarantee the accuracy, so will the movement direction of the forging die and spin blacksmith sequence with computer control, a lower forging force are available on complex shape, high precision products, such as the production of many varieties, large size of the turbine blade forgings.

The die movement and degree of freedom of forging equipment are inconsistent. According to the characteristics of deformation limitation of bottom dead point, forging equipment can be divided into the following four forms:

1, limited forging force form: oil pressure direct drive slider hydraulic press.

2. Quasi-stroke limit: hydraulic press driven by crank and connecting rod mechanism.

3, stroke limit mode: crank, connecting rod and wedge mechanism to drive the slider mechanical press.

4. Energy limit: Screw and friction press with screw mechanism.

Hot test of heavy aviation die forging hydraulic press

Hot test of heavy aviation die forging hydraulic press

In order to obtain high accuracy, care should be taken to prevent overload at the bottom dead point, control speed and mold position. Because these will have an impact on forging tolerance, shape accuracy and die life. In addition, in order to maintain accuracy, attention should also be paid to adjusting the slideway gap, ensure stiffness, adjust the bottom dead point and use of auxiliary transmission device and other measures.