8-446 BLACK BUNA 90D BACK-UP RING

HB90446 is an AS568-446 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 8.475 in (215.27 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 9.025 in (229.24 mm). In service, this back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Buna-N (Nitrile) offers reliable performance in both static and dynamic service, the most widely specified general-purpose sealing elastomer. Expect good resistance to greases and lubricants, water, and propane and butane. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Verify compatibility before use with ketones or automotive brake fluid.

It sees regular use in agricultural equipment, hydraulic and pneumatic systems, and construction equipment.

This item is sold individually under part number HB90446. Unit weight is approximately 15.108 g and nominal inside diameter is listed as 8 1/2 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. 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.