HB90466 is an AS568-466 black Buna-N (Nitrile) 90 Shore A Back-Up Ring supplied with an inside diameter of 18.455 in (468.76 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 19.005 in (482.73 mm). In service, this back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.
This material stands up to petroleum-based oils, greases and lubricants, and hydraulic fluids. That behavior comes from the compound itself: Buna-N (Nitrile) delivers reliable performance in both static and dynamic service, strong abrasion and tear resistance. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). Applications involving automotive brake fluid or ozone and direct sunlight call for a different compound.
You will find this material specified across general industrial maintenance, agricultural equipment, and fluid power.
Stocked as HB90466 and sold individually. Unit weight is approximately 32 g. Review your operating media and conditions against this specification before installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.
description 8-466 BLACK BUNA 90D BACK-UP RING
Actual_CS 0.275 inch (6.99 mm)
Actual_ID 18.455 inch (468.76 mm)
Actual_OD 19.005 inch (482.73 mm)
ProductCode Description O-Rings - Backup Rings