8-046 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90046, an AS568-046 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 4.239 in (107.67 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 4.379 in (111.23 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

As a material, Buna-N (Nitrile) is valued for strong abrasion and tear resistance, low compression set under sustained load. Expect good resistance to greases and lubricants, petroleum-based oils, and propane and butane. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). Verify compatibility before use with strong acids or ketones.

Common environments for this compound include agricultural equipment, fluid power, and automotive.

Order part number HB90046, sold individually. Unit weight is approximately 0.7453 g and nominal inside diameter is listed as 4 1/4 inch. Review your operating media and conditions against this specification before installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.