Closed die forgings are sometimes referred to as impression die forging.
In the process of manufacturing custom die forgings, the bottom half of the die (mold) is held in place on the bottom table or anvil of the forging press. The top part of the steel die mold is held in place on the ram. Both these dies resemble the completed forged part being made.
A forging press, often just called a press, is used for press forging. There are two main types: mechanical and hydraulic presses. Mechanical presses function by using cams, cranks and/or toggles to produce a preset (a predetermined force at a certain location in the stroke) and reproducible stroke.
The metal work piece (billet) is heated and placed on the lower die. The ram is activated and the top die strikes the bottom die, which fills the contours of both dies, molding the metal into the forged part.
In some cases when forging steel or stainless, the ram die may impact the bottom die several times to ensure all of the contours are filled. With most copper alloys, aluminum alloys, it is only impacted once. In some cases preforming of the billet may be required.
With all the pressure put on the work piece its commonplace to get metal flow between the dies called "flash." However, flash cools relatively quickly and therefore helps block or reduce further flow between the dies. This flash is trimmed off once forging is complete.
Forging provides superior mechanical properties over castings due to the internal grain structure formation in forged parts
The closed die forging process is most often employed for smaller, higher tolerance components.
It is used for most custom die forgings of non-ferrous alloys like brasses and bronzes and also for carbon and alloy steels.
One thing to note, closed die forgings of stainless alloys is commonly performed; however, it is most often done on very simple non-complex parts.
We can supply most all custom die forgings produced in copper and copper alloys (brasses & Bronzes), aluminum alloys, all types of steels, stainless steels and other nickel alloys.