In the real world, bearings become contaminated, and (despite advances in technology) contamination is the leading cause of premature bearing failure.
The harsh working environments typical of the quarry, mining, construction and steel industries require bearings tough enough to withstand abrasive contaminants and frequent vibration. To combat the damaging effects notoriously found in these heavy-duty surroundings, NSK pioneered Tough Steel.
Tough Steel bearings are manufactured with a specially patented steel formula and are designed to reduce flaking and wear caused by contamination. This formula also allows for increased resistance to seizure, resulting in longer bearing life.
Under dirty operating conditions, lubricating oil is easily contaminated. Particles in the lubrication make dents in the contact surfaces of the raceways and rolling elements. Around these dents, jagged "edges" develop where concentrations of working stress accumulate. After repeated use, these edges fragment, causing even more contamination.
The microstructure of Tough Steel allows dents in contact surfaces (commonly called contaminants) to have smoother edges. These smoother edges do not break off as readily or cause as much flaking as the jagged edges found in other bearing steels. Less internal flaking means less contamination in the raceway. Smoother contact surfaces means less fatigue and longer bearing life.
Both ball and roller bearings can be produced in Tough Steel material. When put into operation, here are some of the benefits you can expect.
- Improved seizure resistance
- Improved dimensional stability
- Reduced flaking and wear
- Increased heat resistance.
In testing, Tough Steel has conclusively proven it's longetivity and superior performance with up to ten times the service life under contaminated conditions, up to 5 five-and-a-half times the service life under poor lubrication conditions; and up to twice the service life with clean lubrication.