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

Hard-grade NBR (Buna-N) O-rings at 90 Shore A, built for high-pressure hydraulic and oil sealing where the seal has to resist extrusion and survive repeated pressure cycles. The higher durometer holds its shape better than 70 Shore A in demanding glands and fast-moving rods.

Features

• 90 Shore A hardness resists extrusion in high-pressure glands
• Low compression set for stable, repeatable sealing
• Good oil, fuel, and abrasion resistance at low material cost
• Molded to AS568 and ISO 3601; custom sections cut from cord

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: Pick 90 durometer when system pressure is high or the O-ring risks being squeezed into the clearance gap — the harder compound resists extrusion and nicks far better. Use 70 Shore A for low-pressure or static seals against irregular surfaces, where more flexibility helps.

Q: What pressure can a 90 Shore A NBR O-ring handle?
A: In a well-designed gland it handles typical hydraulic pressures comfortably; for very high pressure add anti-extrusion back-up rings to prevent the seal from being forced into the gap. Gland clearance and surface finish matter as much as the compound.

Q: Is this O-ring rated for sour gas (H2S) service?
A: No. Standard NBR is not rated for H2S or sour service. For sour environments use our HNBR (HSN) O-rings, which are specified for H2S and CO2.

Q: What sizes are available?
A: Standard AS568 dash sizes and ISO 3601 metric sizes are molded and stocked. Non-standard diameters and cross-sections can be cut from extruded cord or custom-molded.

Q: What fluids is NBR 90 compatible with?
A: Mineral and synthetic hydraulic oils, diesel, gasoline, water, and glycol-based fluids. It is not recommended for ketones, esters, strong acids, or prolonged exposure to aromatic hydrocarbons and ozone.

Q: Can you supply custom compounds or hardness?
A: Yes. Beyond 90 Shore A we offer 70 Shore A, FDA-grade, and low-temperature NBR compounds, plus custom sizes and colors on request.