About Forging
OPen-Die Forging
Open-die forging uses flat surfaces to shape hot metal. Open-die forging can handle extremely large pieces (tens-of-thousands of pounds).
Basic shapes come from this type of forge.
Closed-Die Forging
Closed-die forging uses a top and bottom die to force metal into a specific shape. The basic steps are:
Heat
Hammer
Cut
Trim
Cool
Inspect
Heat Treatment
Clean
Plating or Coating
After the platter is cut from the rod, usually another operator places it on a press that cuts away the flash. When the finished piece has cooled sufficiently, the pieces are inspected. Finally, any remaining flash is ground off, the pieces are sent for heat treatment, costing or plating and prepared for distribution.
Cold forging
Cold forging is used for small pieces when it is important to maintain the grain properties of the alloy. Hot forging can change the structure of the metal on a very small scale which is desirable for some finished items but not all.
Some fasteners and pinions are formed this way.