process

Closed die or impression forging is done in one or in a series of die impressions or die cavities. These dies are often heated to maintain proper forging temperatures. This type of forging is often done in heavy presses as well as with hammers.

Workpieces may be round or rectangular in cross section, or flat discs. Simple shapes may be forged in a single stroke while more complicated pieces may pass through several strokes and die cavities before achieving their final form. During the final forging, a thin layer of metal, called the “flash” will flow out between the dies. This flash is subsequently removed manually or by special trimming dies. With a carefully controlled pre-form size and shape, flashless forging is possible. As in open die forging, graphite lubricants are used. Water or oil based, such lubricants enhance metal flow, minimize die wear, retard heat loss, and aid in releasing the work from the die. The final forged part is much closer to net shape than with open-die forging and is of higher quality, both dimensionally and metallurgically.

Seamless ring forging is the circumferential expansion and cross section of a centrally pierced, disk shaped workpiece. Both exterior and interior profiles can be obtained on the ring rolling machine which consists of a mandrel or undriven wheel and a driven outer wheel. As the distance between the rollers and mandrel closes, the forging action takes place. Products produced include gear blanks, bearing races, valve bodies, wheels, and turbine components.