APG stocks the HB90034, an AS568-034 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 2.114 in (53.7 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 2.254 in (57.25 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
Buna-N (Nitrile) is specified here for economical choice for high-volume maintenance programs, reliable performance in both static and dynamic service. This material stands up to petroleum-based oils, water, and greases and lubricants. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Applications involving ketones or polar solvents call for a different compound.
Typical settings include automotive, fluid power, and construction equipment.
This item is sold individually under part number HB90034. Unit weight is approximately 0.3757 g and nominal inside diameter is listed as 2 1/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.
description 8-034 BLACK BUNA 90D BACK-UP RING
Actual_CS 0.07 inch (1.78 mm)
Actual_ID 2.114 inch (53.7 mm)
Actual_OD 2.254 inch (57.25 mm)
ProductCode Description O-Rings - Backup Rings