SKF black oxide bearings add a surface layer of protection to promote higher reliability and performance for wind turbines. The coating can be specified for all types of critical bearings in wind turbine systems to help promote higher reliability against widely varying temperatures, speeds, and loads and to resist contaminants, moisture, and chemicals that otherwise could limit bearing lifecycles and increase costs of turbine operation and maintenance. The coated bearings can be introduced into new installations or serve as replacement upgrades.
Black oxide bearings ultimately can increase turbine uptime by enhancing resistance to corrosion and smearing; improving performance in low-lubrication conditions; limiting risk of fretting, micropitting, and cracking; reducing potential damage from aggressive oil additives; and reducing the effects of friction and wear.
The black oxidation surface treatment is applied to a bearing’s rings and/or rollers. The process — involving a chemical reaction at the surface layer of the bearing steel — is performed in an alkaline aqueous salt solution at defined temperatures. Up to 15 different immersion steps create a thin, dark black surface layer delivering a significant performance upgrade for the broad range of bearing types and sizes in wind turbines (up to 2.2m in diameter and up to 1,000 kg per individual bearing component).
Suitable bearing types for the coating include tapered roller bearings, cylindrical roller bearings, spherical roller bearings, and CARB toroidal roller bearings, among others playing vital roles in wind turbine systems.