Free forging (open die forging) is to use strike power or pressure make the metal deformation between upper and lower iron, to obtain the forging parts with required shape and dimensions.

1, Upsetting and local upsetting.


Upsetting is the process to increase cross-sectional area, suitable for discs, block shape etc. In order to avoid billet axial direction bending during upsetting process, the height should be no greater than diameter 2.5-3 times.
Local upsetting is the process to do upsetting in a certain area with only heat the local area.

2, Drawing out, Drawing out with a core bar, expanding holes with a punch.

Drawing out is the process to decrease cross-sectional area and increase longth, suitable for axial, strick etc, to use tagging clamp billets firmly, and constantly flip according to its axis center during striking process by hammers, there are 2 methods: 90°flip and helix flip.Drawing out with a core bar is the process to add a core bar in hollow billets to decrease the thickness of wall and increase longth. Expanding holes is to expand radical direction, there is two ways, one is to use punching cone, the other is to use core bar. The punching cone methods should be done less dimension or easy to expansion broken; the core bar methods is the way to use upper anvil and core bar in hollow billet in continous press to achieve expanding. The upsetting and drawing out is uaually alternate and overlay, sometime one side is in upsetting process while the other is drawing out.

3, (through-hole, blind-hole) pierce.


Piercing is a forging process to punch through hole or blind hole. The common way is two side piercing and one side piercing. The two side piercing is to punch a trial dent for position check firstly, splash some braize in dent in order to get punch easily, to punch 2/3-3/4 of the billet thickness, then overturn the billet and pierce the hole. The one side piercing is punching the hole directly after checking the right position, which is usually used for thinner billet.

4, Bending.

Bending is a forging process to use certain die to make billet bent with required shape. There are two ways, free bending and forming bending.

5, Cutting.

Cutting is to cut billet, remove the extra forging allowance. There are 4 cutting methods, one side cutting, two side cutting, four side cutting and round bar cutting.

6, Other free forging (open die forging) methods.

Twisting: To twist certain angle.

Offset: To offset translation, such as crankshaft.