8-322 BLACK BUNA 90D BACK-UP RING

HB90322 is an AS568-322 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 1.225 in (31.12 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 1.645 in (41.78 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.

Buna-N (Nitrile) offers an economical choice for high-volume maintenance programs, reliable performance in both static and dynamic service. The compound resists many alcohols, hydraulic fluids, and petroleum-based oils. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Exposure to ozone and direct sunlight or ketones will shorten service life.

Maintenance and OEM teams specify it across fluid power, general industrial maintenance, and agricultural equipment.

This item is sold individually under part number HB90322. Unit weight is approximately 1.2131 g and nominal inside diameter is listed as 1 1/4 inch. 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.