Bols Ring Locking System

A patented roll ring locking system that has been created by the means of process facts and needs in rolling mills with respect to the problems observed on most common ring locking systems.

As mostly known, there are two main systems – mechanical and hydraulic – to lock rings on shafts to be used as
rolling rolls all around the world (or hybrid systems allowing to utilize both systems together). All have advantages and disadvantages in comparison to each other based on their design limitations, briefly:

Mechanical Systems

Mechanical Systems works with a wedge for locking the rings on shafts, but as these systems needs to be assembled in shrink fit, whole shaft required to be heated, which creates loss of material properties of shafts effecting the life of usage (creating breakages on shafts). Besides, as the rolling loads are trying to be balanced with a wedge, this huge load usually causes damages on wedges due to the limitation in assembling different materials (shaft/wedge/TC ring) together, which are lasted with ring cracks or breakages.

On the other hand, to solve assembling the different materials; an innovation made by one of the worldwide known company and they’ve created a TC ring with different layers, which are metallurgical bounded to each other and mostly solved the problem; but this has created a new problem of being committed to single supplier with very high prices in comparison to ordinary ones.

Hydraulic Systems

Hydraulic Systems are being designed with a ring type hydraulic cylinder to clutch the rings on shafts by squeezing from one side. In this respect, these hydraulic cylinders are the base of problems usually, due to several reasons:

o They have to be stayed pressurized on the shaft to leave the rings locked or to not let them loose. So, in one hand, O-rings are being necessary to be used for each hydraulic cylinder, which are creating weak points in dirty operational conditions and on each disassemble, they need to be renewed with an additional cost. On the other hand, for each shaft, a hydraulic cylinder is
necessary, which is creating high investment costs. But, besides all, due to operational conditions, as it’s necessary to work under water and grease, these hydraulic cylinders cannot be disassembled properly, which is creating to bear the renewing cost repeatedly.

o Most important of all, due to limited space on the shaft, these hydraulic cylinders are being designed very small, so they can’t create the real required high forces to not let the TC rings to spin/rotate, which usually creates ring damages.

Thanks to our patented BOLS RING LOCKING SYSTEM all above mentioned disadvantages and weaknesses have been solved and further advantages become possible. Our system is also based on hydraulic locking of rings on shaft, but with below stipulated differences in comparison to any competing one:
– For each type/size of shaft you need to invest only one hydraulic cylinder and just for once!
– This hydraulic cylinder removed after assembling/disassembling, so:
o It allows us to design the hydraulic cylinder, big enough to make the locking at correct hydraulic force, which enables to have zero risks of spinning/rotating of rings.
o Assembling and disassembling will be extremely quicker than any other system, without any
consumable cost.
– This system enables us to offer the ring locking mechanism to be used in high torques from 1st roughing
stand to finishing stand with different kinds of rings such as TC (WC-Tungsten Carbide), HSS,
pearlitic/acicular cast iron…etc., which is not possible in any other system to be used before the finishing
stands (even usually used only for leader and finish passes).
Of course, as usual, using ring locking systems have general advantages based on selected ring qualities such as:
– Long pass lifetimes (up to 15 times in comparison to an ordinary cast iron roll) and as a result, reduction on
roll consumption costs
– High utilization of mill due to reduced pass/roll changing times
– Based on above, decrease of fixed costs
– High surface quality on rolled product, more profitable products
– Reduced workload on Roll Turning and Stand Preparation Workshops
Currently, BOLS Ring Locking System is being used in 10 different well-known companies