8-313 BLACK BUNA 90D BACK-UP RING

The HB90313 is an AS568-313 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 0.662 in (16.81 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 1.082 in (27.48 mm). This back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

Expect good resistance to petroleum-based oils, propane and butane, and greases and lubricants. That behavior comes from the compound itself: Buna-N (Nitrile) is specified for the most widely specified general-purpose sealing elastomer, strong abrasion and tear resistance. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Applications involving strong acids or ketones call for a different compound.

Typical settings include construction equipment, general industrial maintenance, and hydraulic and pneumatic systems.

This item is sold individually under part number HB90313. Check the compound against your process media, pressure and temperature before committing to a design. 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.