NoWear coated bearings
NoWear is a wear-resistant carbon coating that can be applied to the rolling elements and inner ring raceway(s) of a bearing (designation suffix L7DA) or only the rolling elements (designation suffix L5DA) (fig. 1).
A physical vapour deposition process applies the wear-resistant carbon coating. Thickness of the coating ranges from 1 to 3 μm, depending on the size of the bearing. The hardness of the coating is 1 200 HV10.
NoWear coated bearing surfaces retain the toughness of the underlying material while adopting the hardness, improved friction properties and wear-resistance of the coating.
During the running-in period, minute amounts of the coating material are transferred to the counter-surfaces. This coating reduces friction and improves resistance against wear and smearing, even in bearings where only the rolling elements are coated.
Long service life
Withstand severe operating conditions
increased risk of smearing
insufficient lubricating film
sudden load variations
rapid speed changes
vibration and oscillations
marine and offshore applications
NoWear coated bearings are not intended for vacuum or other completely dry running applications. The coating does not act as a barrier against oxygen, and is therefore not recommended as a corrosion inhibitor.
The most commonly used NoWear coated bearings have a coating on only the rolling elements (designation suffix L5DA). They are recommended for applications where the bearing load is light to normal, or where vibration and oscillating movements occur.
NoWear coated bearings that have the inner ring raceway(s) and rolling elements coated (designation suffix L7DA) are recommended for any of the following operating conditions:
abrasive contaminants that can cause premature wear
unusual lubrication conditions such as bearings lubricated by the process media
Most SKF rolling bearings can be supplied as NoWear coated bearings. For variants not listed in table 1, contact SKF.
Refer to Cages in the relevant product section of the standard bearing.
Dimension standards, tolerances, internal clearance, permissible misalignment
Refer to Bearing data in the relevant product section of the standard bearing.
The extended bearing service life that NoWear can provide in high-speed, lightly loaded applications is difficult to calculate and depends on a variety of factors. However, experience has shown a multifold improvement in bearing service life.
For greased bearings that operate at speeds near or above the permissible speed, or at high temperatures that shorten the grease life, using NoWear potentially extends relubrication intervals.
When operating under marginal lubrication conditions, NoWear can extend bearing service life.
Owing to the material combination of NoWear/steel in the contact area, the risk of smearing damage is reduced. NoWear coated bearings are recommended for applications with light loads in combination with high speeds, where smearing damage is an issue.
Load carrying capacity, equivalent bearing loads
Refer to Loads in the relevant product section of the standard bearing.
For temperature limits of the bearing, refer to Temperature limits in the relevant product section of the standard bearing.
The NoWear coating withstands temperatures up to 350 °C (660 °F).
Refer to Designation system in the relevant product section of the standard bearing.
The designation suffixes used to identify NoWear coated bearings are:
||Coated rolling elements
||Coated rolling elements and inner ring raceway(s)