8-231 BLACK BUNA 90D BACK-UP RING

Buna-N Back-Up Ring, 2.609 in ID x 0.139 CS, 90A, Black, -40 to 250°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
Buna-N (Nitrile / NBR)
Dash Size
231
Durometer
90 Shore A
Cross Section Type
Round
Color
Black
Minimum Temperature
-40°F (-40°C)
Maximum Temperature
250°F (121°C)
Nominal Cross Section
1/8 inch
Nominal Inside Diameter
2 5/8 inch
Nominal Outside Diameter
2 7/8 inch
Unit of Measure
EA
SKU:
HB90231
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Product Specification

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This back-up ring is supplied in AS568-231 black Buna-N (Nitrile) 90 Shore A measuring an inside diameter of 2.609 in (66.27 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 2.887 in (73.33 mm), catalogued under part number HB90231. It bridges the extrusion gap so the primary seal holds its shape under load.

Buna-N (Nitrile) is specified for the most widely specified general-purpose sealing elastomer, strong abrasion and tear resistance. Expect good resistance to water, many alcohols, and greases and lubricants. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. It should not be specified for service in ozone and direct sunlight or ketones.

You will find this material specified across hydraulic and pneumatic systems, construction equipment, and agricultural equipment.

Stocked as HB90231 and sold individually. Unit weight is approximately 0.9692 g and nominal inside diameter is listed as 2 5/8 inch. Review your operating media and conditions against this specification before installation.
Item
HB90231
Description
8-231 BLACK BUNA 90D BACK-UP RING
Actual Cross Section
0.139 inch (3.53 mm)
Actual Inside Diameter
2.609 inch (66.27 mm)
Actual Outside Diameter
2.887 inch (73.33 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings