According to the movement of the blank, forging can be divided into free forging, upsetting, extrusion, die forging, closed die forging, closed upsetting. Closed and closed upsets have high material utilization due to the lack of flash. It is possible to complete the finishing of complex forgings in one process or several processes. Because there is no flash, the forging area is reduced and the required load is reduced. However, it should be noted that the blank cannot be completely constrained. For this purpose, the volume of the blank must be strictly controlled, the relative position of the forging die must be controlled, and the forging should be measured in an effort to reduce the wear of the forging die.
According to the movement mode of the forging die, forging can be divided into pendulum, swing forging, roll forging, cross wedge rolling, crucible ring and oblique rolling. Pendulum, swing swaged and ring can also be used precision forging processing. In order to increase the utilization of materials, roll forging and cross rolling can be used as a pre-processing process for slender materials. Rotary forging like free forging is also partially formed, which has the advantage that the forging force can also be formed with a smaller forging force than the forging size. This type of forging method, including free forging, causes the material to spread from the vicinity of the die surface toward the free surface during the machining. Therefore, it is difficult to ensure the accuracy. Therefore, the direction of movement of the forging die and the swaging process can be controlled by a computer and can be used low. The forge force results in a product with a complex shape and high precision. For example, forgings such as steam turbine blades with large variety and size are produced.