Black oxide

Black oxide
Black oxidation of rings and rollers (suffix L4B) improves reliability and performance in highly demanding applications, especially under low load conditions and vibrations. In addition, it provides anti-corrosion protection and improves the lubricant adhesion on the surfaces.  Therefore, it is highly recommended to use black oxidation for tapered roller bearings on the high speed shaft and for cylindrical roller bearings in the planetary and parallel shaft stage.

More about SKF bearings:

SKF logo