Forging is one of the important methods of metal plastic processing. The main purpose of forging is: forming and modification (improvement of mechanical properties and internal structure). The latter is difficult to be realized by other processes. In addition, forging production also has the advantages of metal saving, high production efficiency and great flexibility.
Forging can make the casting structure loose and porous, break the coarse casting structure (dendrite grain) into fine grains, and form fiber structure. When the fiber tissue is reasonably distributed along the part contour, the mechanical properties of the part can be improved. Therefore, the forged parts have high strength and can withstand greater impact load. Under the same impact load, the size of forged parts can be reduced, which saves metal.
Forging can be divided into free forging, die forging, cold heading, radial forging, extrusion, forming rolling, roll forging, rolling, etc. according to the forming method. The deformation of the blank under pressure is basically not subject to external restrictions, which is called free forging, also known as open forging. The blank deformation of other forging methods is limited by the die, which is called closed mode forging. The forming tools for forming rolling, roll forging, rolling, etc. have a relative rotary movement with the blank, which pressurizes and forms the blank point by point and gradually, so it is also called rotary forging.