For the intricate business of Radial–axial ring rolling (RARR), the end result may appear to be a small thing – a seamless round ring. But when you’re talking about steel rings, not just plastic ones, it goes without saying that the technology involved is intense, nevermind the intensity of the heat to render the metal malleable.
May this diagrammatic picture speak a thousand words regarding the make-up of RARR machines: In the ring rolling process, two rollers (one idle and one driven) are used to roll a smaller diameter ring into a precise, larger diameter ring with a reduced cross-section. During industrial metal ring rolling, edging rollers are typically used to maintain a constant width throughout the forming operation.
During the RARR process, the motions of the axial rolls are very complicated and the latest developments have ensured more accuracy than ever. An initial ‘ring blank’ is gradually changed from a shape with a small outer diameter and thick section into one with a large outer diameter and thin section using a continuous rolling method. RARR leads to a favourable grain flow and good surface quality, which are the most important qualities of rolled rings.
Before the advent of modern hydraulics and computerised controls, the process of ring rolling was a manual one, in which a skilled operator had to use all his experience to manipulate the command levers and successfully negotiate the workings of the rolling cycle in order to produce a quality rolled ring.
Rolling seamless rings on RARR machines today places huge demands on the machinery, the computer systems and the ably qualified operators making it all happen. Facilitating something with reproducibility and working on defining rolling parameters are all in the ballpark for the systems various handlers. Needless to say, the high degree of rolling process automation ensures maximum utilisation of machine capacity. The result is a stable, cost-effective production process.