Oring Cad
AS568-427 Buna-N 90 Duro Black O-Ring for 4-3/4 ID X 1/4 CS

Buna-N O-Rings 90 Duro Black BN900100-427

$ 2.62 per Each
Minimum Order Quantity (MOQ): 25
On Backorder

Material Buna-N
Cross Sectional Shape Round
Hardness 90
Dash 427
Fractional
  • ID: 4-3/4
  • CS: 1/4
  • OD: 5-1/4
Actual (Inch)
  • ID: 4.725 ± 0.033
  • CS: 0.275 ± 0.006
  • OD: 5.275
Actual (Metric)
  • ID: 120.02 ± 0.84
  • CS: 6.99 ± 0.15
  • OD: 134.000

Buna-N (Nitrile) O-rings are made from a synthetic rubber copolymer of acrylonitrile (ACN) and butadiene. They are among the most widely used sealing materials due to their excellent resistance to oils, fuels, and many chemicals. Nitrile O-rings provide high mechanical strength, outstanding wear resistance, and good tensile strength, making them ideal for automotive, industrial, and aerospace applications.

Buna-N Recommended Uses

Seals and gaskets, fuel systems, hydraulic systems, oil and gas industry, automotive applications, general-purpose applications.

Buna-N Not Recommended

Brake fluid, ozone, UV exposure, phosphate esters, chlorinated hydrocarbons, aromatic hydrocarbons, ketones, strong acids, atmospheric aging.

Buna-N Limitations

  • Not suitable for ozone, sunlight, or weathering exposure.
  • Limited performance in high-temperature environmen.
  • Not ideal for strong acids and alkalis.
  • Not recommended for applications requiring low compression set.
Buna-N Usable Temperature Range

-30 to 250°F (-34 to 121°C)

Buna-N Also Known As

Buna-N, Nitrile, NBR, Nitrile Butadiene Rubber.