NBR Nitrile O-Ring 90 Shore A Hard Grade for High-Pressure Oil Service
NBR Nitrile O-Ring 90 Shore A — Hard Grade for High-Pressure Oil Service
NBR (Buna-N) 90 Shore A O-rings for oil-service replacement are selected together with the oil formulation, pressure cycle and gland dimensions. Provide fluid additives, normal and peak temperatures, and pressure peaks. For moving rods, include stroke speed and lubrication conditions; nominal hardness alone does not establish dynamic-sealing performance.
| Material | NBR (Nitrile / Buna-N) |
|---|---|
| Hardness | 90 Shore A (hard grade) |
| Temperature | Confirm temperature limits for the selected NBR compound |
| Color | Black |
| Standards | AS568, ISO 3601, DIN 3771 |
| Sealed Media | Specify oil or fuel formulation and additives for compound compatibility review |
| Not Recommended | Ozone, ketones, esters, strong acids, aromatic hydrocarbons (long term), H2S |
Features
- 90 Shore A nominal hardness reviewed with pressure and operating clearance
- Compression-set and pressure-cycle requirements specified for the application
- NBR material family for compatible oil service; confirm fluid and wear requirements
- Specify AS568 dash size or metric dimensions; molded rings and joined cord loops are distinct constructions
Applications
High-pressure hydraulic cylinders, oilfield manifolds, gearboxes, fuel systems, water pumps, and general-purpose oil seals under elevated pressure.
FAQ
Q: When should I choose 90 Shore A instead of 70 Shore A NBR?
A: Compare the specified compounds against pressure, clearance and seal squeeze. Higher hardness can improve extrusion resistance but changes compression and installation force. Include motion and lubrication requirements for a dynamic gland.
Q: What pressure can a 90 Shore A NBR O-ring handle?
A: A pressure rating requires the complete gland design and compound data. Provide maximum pressure, transient peaks, temperature and clearance under load. Review backup-ring placement, surface finish and pressure direction before specifying the assembly.
Q: Is this O-ring rated for sour gas (H2S) service?
A: This product description does not establish sour-service qualification. Provide gas composition, pressure, temperature, decompression conditions and required tests. An alternative polymer such as HNBR also needs compound-specific qualification.
Q: What sizes are available?
A: Send an AS568 dash number or metric inner diameter and cross-section, with tolerances and quantity. Specify a molded continuous ring for the relevant gland. Joined cord loops need separate joint and leakage requirements and must not be assumed equivalent for pressure service.
Q: What fluids is NBR 90 compatible with?
A: Compatibility depends on the exact fluid formulation, additives and temperature. Provide the oil or fuel designation, cleaning fluids and exposure duration. Review compound data rather than assuming all mineral or synthetic fluids share the same compatibility.
Q: Can you supply custom compounds or hardness?
A: Include alternative hardness, low-temperature or color requirements with the drawing. Food-contact applications require the applicable regulation and compound documentation; NBR material alone does not establish compliance.
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