Press Release

Now Available: Long-Life Work Roll Bearings for Rolling Mills

Significantly longer service life helps cut CO2 emissions and resource consumption.

NSK Ltd. (NSK; Headquarters: Tokyo, Japan; President & CEO: Toshihiro Uchiyama) has developed a line of long-life four-row sealed tapered roller bearings with water-resistant grease. These new work roll bearings for rolling mills*1 deliver on the need for bearings that last.

The bearings are packed with a newly developed grease that provides long service life even under severe conditions, such as when water enters the bearing. This longer service life reduces maintenance costs and increases operational efficiency. Since these bearings need replacement less often, they help to reduce CO2 emissions and resource consumption.

*1: Rolling mills typically use pairs of work rolls to roll slabs of steel or other metals into specific shapes such as sheets.

Long-Life Work Roll Bearings for Rolling Mills

Development Background

Work roll bearings (pictured) used in rolling mills face an extremely tough environment. They bear heavy loads at high speeds and temperatures while under constant exposure to water sprays and metal particles. These severe conditions can lead to premature bearing failure (flaking

*2: Flaking occurs when fatigue causes small pieces of bearing material to split off from the smooth surface of the raceway. This creates coarse regions that eventually make the bearing inoperable.


1. Improved Design With Seal, Higher Load Capacity
The seal impedes water from entering the bearing and reduces grease refill during maintenance.
Boasts an increased load rating (load capacity) due to an optimized internal design.
2. Improved Lubrication-Newly Developed Water-Resistant Grease
Optimized grease composition creates a thicker oil film and protective layer between the raceway and rollers, inhibiting direct contact without lubrication.
Special grease additives inhibit rusting, significantly boosting service life in conditions where water may enter the bearing.
3. Over Double the Service Life
Real world tests prove these new bearings can achieve a service life over 16 months, while conventional products typically last less than 8 months.

Product Benefits

Significantly longer life benefits steel manufacturers through fewer replacements and higher operational reliability. Longer life also reduces material and energy consumption (including CO2 emissions) relative to the replacement cycles of conventional models.

Product Benefits

NSK will continue to develop and produce new products geared toward realizing a sustainable society.