8-018 BLACK BUNA 90D BACK-UP RING

Buna-N Back-Up Ring, 0.739 in ID x 0.07 CS, 90A, Black, -40 to 250°F

Status
Available
Est. Ship Date
30 Oct 2026
Material
Buna-N (Nitrile / NBR)
Dash Size
18
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
1/16 inch
Nominal Inside Diameter
3/4 inch
Nominal Outside Diameter
7/8 inch
Unit of Measure
EA
SKU:
HB90018
Please login to see price and add to cart

Product Specification

-
This back-up ring is supplied in AS568-018 black Buna-N (Nitrile) 90 Shore A measuring an inside diameter of 0.739 in (18.77 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 0.879 in (22.33 mm), catalogued under part number HB90018. It installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

As a material, Buna-N (Nitrile) is widely chosen for reliable performance in both static and dynamic service, an economical choice for high-volume maintenance programs. The material holds up against greases and lubricants, petroleum-based oils, and many alcohols. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). It should not be specified for service in strong acids or automotive brake fluid.

Common environments for this compound include construction equipment, fluid power, and general industrial maintenance.

Order part number HB90018, sold individually. Unit weight is approximately 0.144 g. Check the compound against your process media, pressure and temperature before committing to a design.
Item
HB90018
Description
8-018 BLACK BUNA 90D BACK-UP RING
Actual Cross Section
0.07 inch (1.78 mm)
Actual Inside Diameter
0.739 inch (18.77 mm)
Actual Outside Diameter
0.879 inch (22.33 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings