HB90204 is an AS568-204 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 0.359 in (9.12 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 0.637 in (16.18 mm). In service, this back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
As a material, Buna-N (Nitrile) is widely chosen for the most widely specified general-purpose sealing elastomer and an economical choice for high-volume maintenance programs. The compound resists hydraulic fluids, greases and lubricants, and water. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Verify compatibility before use with strong acids or ketones.
Common environments for this compound include construction equipment, general industrial maintenance, and agricultural equipment.
This item is sold individually under part number HB90204. Unit weight is approximately 0.1842 g. 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.
description 8-204 BLACK BUNA 90D BACK-UP RING
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 0.359 inch (9.12 mm)
Actual_OD 0.637 inch (16.18 )
ProductCode Description O-Rings - Backup Rings