Black oxide coating of rings and rollers improves reliability and performance in highly demanding applications, especially under low load conditions and high vibration. In addition, it improves corrosion protection and lubricant adhesion on the bearing surfaces.
SKF also offers customized black oxide coating layers that are optimized for best tribological results and highest bearing performance, produced using well-defined processes and fine tuned to the individual steel grade, bearing type and size. SKF’s evaluation and quality control technology for the black oxide application process includes a scanning electron microscope and a patented examination method.
NoWear is a wear-resistant surface coating that applies a low-friction carbon coating on the bearing inner ring raceway(s) and/or the rolling elements. It can withstand long periods of operation under marginal lubrication conditions. For additional information, refer to NoWear coated bearings.
INSOCOAT bearings are standard bearings that have the external surfaces of their inner or outer ring plasma-sprayed with an aluminium oxide, impregnated with a resin sealant, to form a coating. It offers resistance to the damage that can be caused by the passage of stray electric current through the bearing. For additional information, refer to INSOCOAT bearings.
Other coatings are available that provide an alternative to stainless steel bearings (especially for ready-to-mount bearing units) that are used in a corrosive environment.
Features for special requirements
SKF provides many more bearing variants, in addition to those presented in the product sections, for accomplishing various tasks and satisfying special application needs. Among the more common special variants produced by SKF are:
- special chamfers – e.g. with a larger radius or with a modified shape (fig. 1)
- additional anti-rotation slots in the outer ring (standard for some bearing types, such as four-point angular contact ball bearings (table 1, fig. 2)
- threaded holes in the rings to accommodate eye bolts to ease lifting (fig. 3)
- sensors – e.g. to aid mounting (fig. 4) or for monitoring speed and direction of rotation (fig. 5)
- measuring reports, material certificate, additional inspections
- tailor-made bearings and units (fig. 6 and fig. 7)