Closed die forgings

Closed die forging sometimes referred to as impression die forging comprises of a die on the anvil which resembles a mould, the ram which falls and strikes the top of the work piece can also be equipped with a die. The metal work piece is heated and placed on the lower die while the ram falls down forcing the metal to fill the contours of the die blocks. The ram may impact the work several times to ensure all of the contours are filled, with all the pressure put on the work piece its common place to get metal flow between the dies called flash, however the flash due to its decreased size cools relatively quickly and therefore helps block or reduce further flow between the dies. This flash will have to be trimmed off once forging is complete.

Advantages

Hot forging prevents work hardening associated with cold forming

Parts of sizes up to 25 tons can be produced with closed die forging

Closed die forging can produce near net shapes that will require only a small amount of finishing

Economic for large runs of product

Forging provides superior mechanical properties over castings due to the internal grain structure formation in forged parts