The HB90332 is an AS568-332 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 2.35 in (59.69 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 2.77 in (70.36 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.
This material stands up to many alcohols, hydraulic fluids, and greases and lubricants. That behavior comes from the compound itself: Buna-N (Nitrile) delivers the most widely specified general-purpose sealing elastomer, strong abrasion and tear resistance. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Verify compatibility before use with ozone and direct sunlight or ketones.
It sees regular use in construction equipment, general industrial maintenance, and automotive.
Order part number HB90332, sold individually. Unit weight is approximately 2.15 g. 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.
description 8-332 BLACK BUNA 90D BACK-UP RING
Actual_CS 0.21 inch (5.33 mm)
Actual_ID 2.35 inch (59.69 mm)
Actual_OD 2.77 inch (70.36 mm)
ProductCode Description O-Rings - Backup Rings