Forging Processes

Open Die Forging

Open die forging involves the shaping of heated metal parts between a top die attached to a ram and a bottom die attached to a hammer, anvil or bolster. Metal parts are worked at their appropriate temperatures, ranging from 500°F to 2400°F, and gradually shaped into the desired configuration through the skillful hammering or pressing of the workpiece.


Difference between open die forging and closed die forging?

  • While impression or closed die forging confines the metal in dies, open die forging is distinguished by the fact that the metal is never completely confined or restrained in the dies. Most open die forgings are produced on flat dies. However, round swaging dies, V-dies, mandrels, pins and loose tools are also used depending on the desired part configuration and its size.
  • Although the open die forging process is often associated with larger, simpler-shaped parts such as bars, blanks, rings, hollows or spindles, in fact it can be considered the ultimate option in “custom-designed” metal components. High-strength, long-life parts optimized in terms of both mechanical properties and structural integrity are today produced in sizes that range from a few pounds to hundreds of tons in weight. In addition, advanced forge shops now offer shapes that were never before thought capable of being produced by the open die forging process.

Rolled Ring Forging

  • The ring rolling process starts with a circular preform of metal that has been previously upset and pierced (using the open die forging process) to form a hollow “doughnut.” This doughnut is heated above the recrystallization temperature and placed over the idler or mandrel roll. This idler roll then moves under pressure toward a drive roll that continuously rotates to reduce the wall thickness, thereby increasing the diameters (I.D. and O.D.) of the resulting ring.
  • Seamless rolled rings can be produced in configurations ranging from flat, washer-like parts to tall, cylindrical shapes, with heights ranging from less than an inch to more than 9 feet. Wall thickness to height ratios of rings typically range from 1:16 up to 16:1, although greater proportions can be achieved with special processing. The simplest and most commonly used shape is a rectangular cross-section ring, but shaped tooling can be used to produce seamless rolled rings in complex, custom shapes with contours on the inside and/or outside diameters.
  • Small or large quantities of open die or rolled rings
  • Up to 252″ maximum outside diameter
  • Up to 49″ maximum face height
  • Rolled ring weights to 60,000 lbs., open die weights to 300,000 lbs.
  • Ring segmenting, parting and splitting
  • Custom-designed heat treat, machining, sawing and material handling equipment for complete in-house ring processing

Hybrid “Semi Closed” Die Forging