NBR 90 Shore A O-Rings for High Pressure Hydraulic Glands - AS568 Standard

NBR 90 Durometer O-Rings for High Pressure Hydraulic Glands

NBR O-rings at 90 durometer (90 Shore A) built for high-pressure hydraulic glands where the seal has to resist extrusion and hold under repeated pressure cycles. The hard compound stays put in the groove instead of being forced into the clearance gap, which is the usual failure mode in demanding hydraulic systems.

Features

• 90 durometer resists extrusion in high-pressure hydraulic glands
• Low compression set for stable, repeatable sealing over cycles
• Good oil, fuel, and abrasion resistance at low material cost
• Molded to AS568, ISO 3601, and DIN 3771; custom sizes on request

Applications

High-pressure hydraulic cylinders, presses, power units, directional valves, manifolds, injection molding machines, and other equipment where the O-ring sees high pressure and a visible clearance gap.

FAQ

Q: What pressure can a 90 durometer NBR O-ring handle?
A: In a correctly sized gland it handles typical hydraulic pressures well; when the clearance gap is large or pressure is very high, add anti-extrusion back-up rings. Gland clearance and surface finish decide the real limit more than the compound alone.

Q: Why 90 durometer instead of 70 Shore A for high pressure?
A: The harder 90 compound resists being squeezed into the gap and survives nicks and extrusion far better. Use 70 Shore A for lower-pressure or static seals where more flexibility helps seat the seal.

Q: What gland clearance should I design to?
A: Keep the radial clearance within AS568 and ISO 3601 gland limits — tighter clearance lets the O-ring take more pressure. Send us your pressure and gap and we will recommend the hardness and whether back-ups are needed.

Q: What sizes and standards are available?
A: Standard AS568 dash sizes, ISO 3601 metric, and DIN 3771 are molded and stocked; non-standard diameters and cross-sections are custom-molded.

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

Q: Can you supply other NBR grades?
A: Yes. Alongside 90 durometer we offer 70 Shore A, FDA, and low-temperature NBR compounds, plus custom hardness and colors on request.