Forging is a processing method which using forging machinery to put pressure on the metal blank, makes it to produce plastic deformation to obtain a certain mechanical properties, shape and size, which is a part of forging and stamping. By forging can eliminate the defect like as-cast loose in smelting process, optimize the microstructure, at the same time, due to the preservation of the complete metal streamline, the mechanical properties of forgings are generally superior to those of the same materials. The important parts with high load and severe working conditions in the relevant machinery are use forgings. Except for the simple form of rolled sheet, section or welder.
According to the deformation temperature, the forging can be divided into hot forging (the forging temperature is higher than the recrystallization temperature of the billet metal), warm forging (the forging temperature is lower than the recrystallization temperature of the metal), and cold forging (normal temperature). The recrystallization temperature of the steel is about 460 ℃, but generally people view 800 ℃ as a dividing line, higher than 800 ℃ is hot forging; the temperature between 300 ~ 800 ℃ is warm forging.
Closed die forging and closed die upsetting
The use ratio of material is high for there is no flash. The finishing of complex forgings may be accomplished with one or more processes. Since there is no flash, the force area of forging is reduced and so as the required load. However, it should be noted that the blank should not be completely restricted. Therefore, it is necessary to strictly control the volume of the blank, the relative position of the forging die and to measure the forgings, try to reduce the wear of the forging die.