AT Bearing 20x32x7mm MS chrome steel Metal shielded (6804zz)
These bearings are made from SAE 52100 chrome steel (GCr15), with carbon steel bearing cages. They have dual stainless steel shields that contact the outer ring only, for zero friction and good lube retention. Shields are held in place with a snap ring for easy removal and cleaning.. Chrome steel offers the best bending strength and fracture resistance of all the bearing materials, but it is not as hard (60-66 rockwell vs. 80-90 rockwell chart hardness) or long wearing as ceramic silicon nitride or silicon carbide ball bearings.
Use these bearings for the lowest possible friction drag, easy cleaning and oiling, but less dirt protection than rubber seals. Ideal for inside sealed gearboxes, or clean indoor racing, or any other application that won’t be exposed to extreme dirt, dust and water.
(for best strength and corrosion resistance for salt water etc, use ceramic Si3N4 bearings)
Bearings manufactured from chrome steel can operate at continuous temperatures up to 120°C.
(for operating temps up to 800°C use ceramic Si3N4 bearings)