O-ring: 340 NBR 90A (AS568A)
Dimensions:
Inside diameter (ID): 85.09 ± 0.61 mm
Cross‑section (CS): 5.33 ± 0.13 mm
Material:
NBR (Nitrile Butadiene Rubber), hardness 90A
Good resistance to petroleum oils, hydraulic fluids, and many fuels; limited resistance to ozone and weathering compared with EPDM or silicone.
AS568A Reference:
AS568A size code: 340
Standard tolerance and dimensional series per AS568A specification
Application notes:
Suitable for static and low-dynamic sealing where high hardness is acceptable.
Higher hardness (90A) increases extrusion and compression set resistance but reduces conformability; ensure mating surface finish and gland design account for reduced elasticity.
Verify chemical compatibility with specific fluids and operating temperatures; NBR typical temp range: approximately -30°C to +120°C (application-dependent).
For dynamic applications or exposure to ozone/UV, consider alternative elastomers (e.g., fluoroelastomer, EPDM, silicone).
Installation and gland recommendations:
Ensure gland dimensions and tolerances follow AS568A guidance adjusted for material hardness.
Provide adequate lubrication during assembly to avoid nicking; avoid incompatible lubricants that may swell NBR.
Inspect for proper squeeze and uniform compression to achieve reliable sealing without excessive deformation.
Quality and testing:
Inspect O-ring visual finish for cuts, voids, or surface defects.
Perform dimensional checks per specified tolerances.
Consider compression set and aging tests for critical or high-temperature applications.
Ordering example:
Part description: O‑ring AS568A #340, ID 85.09±0.61 mm, CS 5.33±0.13 mm, NBR 90A.
Specify quantity, required certification (e.g., material test report), and any special packaging or cleanliness requirements.
O-ring: 340 NBR 90A (AS568A)
Dimensions:
Inside diameter (ID): 85.09 ± 0.61 mm
Cross‑section (CS): 5.33 ± 0.13 mm
Material:
NBR (Nitrile Butadiene Rubber), hardness 90A
Good resistance to petroleum oils, hydraulic fluids, and many fuels; limited resistance to ozone and weathering compared with EPDM or silicone.
AS568A Reference:
AS568A size code: 340
Standard tolerance and dimensional series per AS568A specification
Application notes:
Suitable for static and low-dynamic sealing where high hardness is acceptable.
Higher hardness (90A) increases extrusion and compression set resistance but reduces conformability; ensure mating surface finish and gland design account for reduced elasticity.
Verify chemical compatibility with specific fluids and operating temperatures; NBR typical temp range: approximately -30°C to +120°C (application-dependent).
For dynamic applications or exposure to ozone/UV, consider alternative elastomers (e.g., fluoroelastomer, EPDM, silicone).
Installation and gland recommendations:
Ensure gland dimensions and tolerances follow AS568A guidance adjusted for material hardness.
Provide adequate lubrication during assembly to avoid nicking; avoid incompatible lubricants that may swell NBR.
Inspect for proper squeeze and uniform compression to achieve reliable sealing without excessive deformation.
Quality and testing:
Inspect O-ring visual finish for cuts, voids, or surface defects.
Perform dimensional checks per specified tolerances.
Consider compression set and aging tests for critical or high-temperature applications.
Ordering example:
Part description: O‑ring AS568A #340, ID 85.09±0.61 mm, CS 5.33±0.13 mm, NBR 90A.
Specify quantity, required certification (e.g., material test report), and any special packaging or cleanliness requirements.