Ring Forging

 

The production of seamless forged rings is often performed by a process called ring rolling on rolling mills. These mills vary in size to produce forged rings with outside diameters of just a few inches to over 300 inches and in weights from a single pound up to over 300,000 pounds.

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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.

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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.

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