Fabrication processes for seamless forged rings typically take the form of ring rolling, which is produced on rolling mills. The mills used in such work exist in a range of sizes in order to make rings in diameters ranging from mere inches to those spanning 300 or more inches. It is also possible to create rings weighing anywhere from 16 ounces all the way to several hundred thousand pounds.
The Process of Seamless Rolled Ring Forging
Seamless rolled ring forging begins by taking a circle-shaped metal preform that has already been pierced via open die forging as well as upset. A doughnut shape results from these steps. Then, the shape will be heated beyond the temperature required for recrystallization before it is set above the mandrel roll or idler. The roll is then made to move in the direction of the drive roll, which will rotate on a continuous basis so that the wall’s thickness is reduced and the ring’s diameters will be increased.
Different Configurations for Seamless Rings
It is possible to fabricate seamless rings in an array of configurations, including flat parts resembling washers to taller cylinders, which can reach over 9 feet in height. Broadly speaking, the ratios of wall thickness to ring height tend to range from 1:16 to 16:1. However, it is possible to adjust these proportions upward, provided special types of processing can be undertaken.
Most Popular Shaped Rings
The most popular and simply shaped ring made is that of the rectangular-shaped cross-section model. It should be noted, though, that it is possible to utilize shaped tooling methods to make seamless rolled ring options in any number of more complicated, customized shapes characterized by contouring on the external and internal diameters.
Making ring preforms via open die forging techniques:
1. The starting stock that has been cut to size based on weight will be rounded before being upset in order to attain needed structural strength as well as directional graining.
2. Piece will then be punched and pierced to form the “doughnut” required for the seamless rolled ring forging process.
3. The finalized preform can now be placed onto the ring mill to begin rolling process.
4. The process of ring rolling starts as the idler applies pressure onto the preform sitting on the drive roll.
5. While the pressure continues to reduce the thickness of the wall, the diameters of the ring can be increased. Axial rolls work to maintain control over the ring height throughout the entire process.
6. This continues as long as necessary for the intended size to be attained.