There is an increasing need for expanders within the forging industry due to a reduction in ring tolerances. Fontijne Grotnes expanders are used to calibrate the ring in order to minimize machining allowances and to eliminate local stresses. This greatly reduces the required amount of machining as the ring is closer to its final shape and more stable during post operations. Other benefits of the Fontijne Grotnes expander in the ring rolling process are:

Applications
Calibrated seamless rolled rings are used for slewing bearings, flanges, gearrings for a wide variety of applications such as wind turbines, offshore technology, construction machinery, automotive and in the aerospace industry to fabricate jet engine parts of exotic alloys with tight tolerances.