Steel making rolls used by BHP's Slab and Plate Division in Wollongong, Australia, rotate on Morgoil bearings and any damage to these causes costly stoppages to production while the bearings are replaced. The bearings are protected by a lip seal that runs on an end plate cover that retains grease in the bearing housing and prevents ingress of mill water and the general corrosive environment.

The original seal end plates were continually failing inside their allotted service life and the fault was traced to excessive groove wear at the seal interface. All attempts to correct the problem by changing the material of the working surfaces failed to improve the situation: - the microporosity that is inherent to hard chrome plating allowed water to penetrate to the base, cause corrosion, then flaking of the hard chrome, which in turn damaged the seal. - stainless steel welding, as well as causing distortion to the seal end plates, is not cost effective as the rubber lip seal still wears large grooves into the surface.

The basic problem is that the metallic surfaces when stressed by continuous rotating movement undergo plastic deformation. This type of wear has been noted in many instances of rotating soft seals against metals regardless of their hardness values. The answer to this problem was to change the nature of the interface by substituting an inelastic surface for the metal - C-Ramic coatings are inelastic materials and offer an ideal solution.

The typical working life for a seal end plate was considered to be three months, however in June 1989, new seal end plates were C-Ramic coated and polished to a surface finish of approx 10 microinches.
They are still IN SERVICE !

The inelastic nature of the C-Ramic coating, the excellent surface finish and the low co-efficient of friction against the lip seal is performing beyond all expectations.

All new seal end plates are now C-Ramic coated before service and any worn seal end plates are reclaimed by metalspraying and then C-Ramic coated. Many thousands of dollars have been saved directly by using a C-Ramic coating to prevent wear. Valuable production time added to this operation has increasing its efficiency and profitability.

If you require extended durability in situations where seal wear is costing excess money and increased down time, contact the experts at C Ramic.