This back-up ring is supplied in AS568-045 black Buna-N (Nitrile) 90 Shore A built to an inside diameter of 3.989 in (101.32 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 4.129 in (104.88 mm), catalogued under part number HB90045. It allows a standard o-ring to operate at higher pressures than it could unsupported.
It resists hydraulic fluids, petroleum-based oils, and propane and butane. 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. Exposure to ozone and direct sunlight or ketones will shorten service life.
Maintenance and OEM teams specify it across agricultural equipment, construction equipment, and fluid power.
Order part number HB90045, sold individually. Unit weight is approximately 0.687 g and nominal inside diameter is listed as 4 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation.
Description 8-045 BLACK BUNA 90D BACK-UP RING
Actual Cross Section 0.07 inch (1.78 mm)
Actual Inside Diameter 3.989 inch (101.32 mm)
Actual Outside Diameter 4.129 inch (104.88 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings