8-020 BLACK BUNA 90D BACK-UP RING

The HB90020 is an AS568-020 black Buna-N (Nitrile) 90 Shore A Back-Up Ring supplied with an inside diameter of 0.864 in (21.95 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 1.004 in (25.5 mm). This back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

As a material, Buna-N (Nitrile) is specified for low compression set under sustained load, strong abrasion and tear resistance. This material stands up to petroleum-based oils, greases and lubricants, and many alcohols. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Verify compatibility before use with ketones or automotive brake fluid.

Common environments for this compound include fluid power, general industrial maintenance, and agricultural equipment.

Order part number HB90020, sold individually. Unit weight is approximately 0.16 g and nominal inside diameter is listed as 7/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.