Closed Die Forging Education


Through our affiliation with the Forging Industry Association, EGI is able to offer educational material on the forging process. All information developed by the Forging Industry Association is reprinted with permission.

Closed die forging —

The shaping of hot metal completely within the walls or cavities of two dies that come together to enclose the workpiece on all sides. The impression for the forging can be entirely in either die or pided between the top and bottom dies. Impression-die forging, often used interchangeably with the term closed-die forging, refers to a closed-die operation in which the dies contain a provision for controlling the flow of excess material, or flash, that is generated. By contrast, in flashless forging, the material is deformed in a cavity that allows little or no escape of excess material.  

What is forging?

Forging is a manufacturing process where metal is pressed, pounded or squeezed under great pressure into high strength parts known as forgings. The process is normally (but not always) performed hot by preheating the metal to a desired temperature before it is worked. It is important to note that the forging process is entirely different from the casting (or foundry) process, as metal used to make forged parts is never melted and poured (as in the casting process).

Why use forgings and where are they used?

The forging process can create parts that are stronger than those manufactured by any other metalworking process. This is why forgings are almost always used where reliability and human safety are critical. But you'll rarely see forgings, as they are normally component parts contained inside assembled items such airplanes, automobiles, tractors, ships, oil drilling equipment, engines, missiles and all kinds of capital equipment - to name a few.

Types of Forging Processes

  • Closed Die or Impression  Die Forging
  • Open Die Forging
  • Rolled Ring Forging