Die Forging: Their types , working principle and application

Die forging:

The Die forging process are developed for produce single or mass production of hundreds parts. Die forging process the power hammer is raised up and suddenly “dropped” on the work piece surface and deformed under require shape of die.

The die forging having two types

  1. open die forging process
  2. close die forgings process

Configuration of open die forging process:

open die forging process

In the open die forging the hammer is connected to upper Die and its deform the work piece. Work piece is placed on the stationary anvil. The open die contact with work piece enclosed to allow flow except where contact by dies. In this reason the operator will be needed to orient and adjust work piece position to getting the desired shape. Mostly the dies are flat surface but some of die specially designed for special operation.

For example, the die shape has a round, concave, or forms of hole or it a cut- off tool. The hammer velocity and force depends on the work piece vertical fall and operator skill.

The dies are run shortly and it appropriate art something and custom work some time the open die is roughly shaped to prepare them subsequent operation. It also used to increase the strength of grain in require direction.

Materials: aluminum alloy, copper alloy, carbon and alloy steel, titanium alloy.

Application of open die forging process:

Large and bulk forging, forging ingots and performed finished forging.

Die material used in open die forging process:

  • Hammer die made from medium alloyed tool steels
  • The small tool and flat impression operation done by use of carbon steel with 0.7 to 0.85% of carbon.
  • High alloy steel for high temperature resistant dies are used for presses and horizontal forging machine alloy steel, cast steel, and tool steel used.

close die forgings:

close die forgings

In close die forgings the work piece are placed between two die halves it carry the impression of desired final shape of work piece. The work pieces are deformed in high pressure of die in closed cavity. The closed die forging is also known as impression – die forging. The work piece are place in die resembling a mold, that is attached to anvil. When the hammer die is shaped in require shape as well and then hammer dropped on work piece, this cause the metal flow in die cavities and filled.


In sufficient of millisecond time the die contact with work piece depends on the size and complexity of parts which hammer dropped in work piece in multiple times in quick succession. The excess amount of metal squeezed out of the die cavity, refer to as flash. In flash cooled together from more rapidly than rest of materials. That cooling of work metal is stronger than metal in the die to help prevent in more flash from forming. It also forced the metal to complete filled together in die cavity. After forcing end flash is removed.

Materials can be forged by using close die forgings:

Aluminium alloys, carbon and alloy steel, copper alloy, beryllium, magnesium alloy, stainless steels, titanium and titanium alloy, nickel alloy, nickel and iron and cobalt super alloys, tantalum and tantalum alloy, niobium and niobium alloy, tungsten alloy, molybdenum and molybdenum alloy.

Application of close die forgings:

Providing forging of automobiles, rail road and mining equipment, trucks, off- highway equipment, tractors, aircraft, energy related engineering production and general mechanical industry.

The variation of impression- die forging is flash less forging or true close die forging. In this type the die cavity completely closed. It used to process of less metal is lost to flash. The starting material for 20 to 45% in flash. The main disadvantage of more cost due to complex die design and require lubrication and work piece placement.

Comparison between open die and closed die forging:

Open die forging

Closed die forging

  • The work metal formed in flat die


  • Work metal are deformed under high pressure
  • Use of large components
  • Used for limited component
  • Poor of dimensional control
  • Precision forging with close dimensional tolerance
  • Die are not expensively
  • It is expensive die
  • Shape of work metal depend upon the operator skill
  • Work shape depends upon shape of die





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