NBR O Ring

NBR O rings, also known as nitrile rubber O rings or Buna-N O rings, are one of the most widely used rubber sealing products in industrial equipment. They are commonly selected when the sealing position comes into contact with petroleum-based oil, fuel, grease, hydraulic fluid, or general mechanical working conditions.

Compared with FKM, EPDM, and silicone, NBR is often a more cost-effective choice for standard oil-resistant sealing. It has good mechanical strength, good wear resistance, and stable sealing performance in hydraulic, pneumatic, automotive, pump, valve, and machinery applications.

For standard black rubber O rings, NBR is usually the first material to evaluate before moving to higher-performance materials such as FKM, HNBR, or FFKM. It works well for many regular industrial sealing needs, especially where oil resistance, dimensional stability, and cost control are all important.

Yuefeng supplies both standard NBR O rings and custom nitrile rubber O rings. The material compound, hardness, size, tolerance, color, and packaging can be adjusted according to the working medium, temperature, pressure, and installation structure.

Main Advantages

• Good resistance to petroleum-based oils and fuels
• Suitable for hydraulic fluid, grease, water, and many general industrial media
• Good wear and abrasion resistance
• Good compression set performance
• Good tensile strength
• Cost-effective for standard sealing applications
• Suitable for standard sizes, custom sizes, and bulk orders

Main Limitations

• Not recommended for long-term outdoor exposure
• Limited resistance to ozone and strong sunlight
• Not suitable for ketones, strong acids, and some aggressive solvents
• Not the best choice for high-temperature chemical environments
• Not suitable for applications that need strong weather resistance

For high temperature, aggressive chemicals, outdoor exposure, steam, or special media, FKM, EPDM, silicone, HNBR, or FFKM may be more suitable.

NBR O rings can be supplied in standard sizes or produced according to drawings and samples. The final material compound, hardness, and tolerance should be selected according to the working medium, pressure, temperature, and installation structure.

For many standard industrial sealing applications, 70 Shore A NBR is commonly used. It offers a balanced combination of flexibility, compression resistance, and sealing stability.

For higher-pressure sealing positions, harder compounds such as 80 or 90 Shore A can be selected. For easier assembly or low-pressure sealing, a softer hardness may be more suitable.

NBR O rings are used in sealing positions where oil resistance, wear resistance, and cost efficiency are required. They are suitable for many industrial and mechanical sealing applications.

Hydraulic Systems

NBR O rings are commonly used in hydraulic cylinders, hydraulic pumps, hydraulic valves, fittings, and pipe connections. They perform well in many oil-based hydraulic fluid environments and are often selected for standard hydraulic sealing positions.

For high-pressure hydraulic systems, hardness, groove design, pressure level, and the need for backup rings should be checked before production.

Pneumatic Equipment

For pneumatic cylinders, air valves, air tools, and automation equipment, NBR O rings can provide stable sealing performance under general air pressure conditions. Hardness and lubrication should be selected according to movement speed and installation structure.

Automotive and Machinery Sealing

NBR O rings are often used in automotive parts, fuel-related components, engines, oil lines, mechanical joints, gearboxes, and industrial machines. The material is suitable for many oil and grease environments where standard rubber sealing performance is required.

Pump and Valve Sealing

In pumps, valves, pipe fittings, and fluid control systems, NBR O rings help prevent leakage of oil, water, grease, or compatible fluids. For chemical fluids or high-temperature media, material compatibility should be checked before choosing NBR.

Before ordering NBR O rings, the sealing condition should be checked first. Size alone is not enough. Material compound, hardness, pressure, temperature, and working medium all affect sealing performance.

Key Information to Confirm Before Ordering

• Inner diameter
• Cross section
• Groove size
• Hardness requirement
• Working temperature
• Working medium
• Static or dynamic sealing
• Pressure condition
• Standard size or custom drawing
• Quantity
• Packaging requirement

For general industrial sealing, 70 Shore A NBR is commonly used. It provides a balanced combination of flexibility, compression resistance, and sealing stability.

For higher-pressure sealing positions, 80 or 90 Shore A may be selected. For low-pressure sealing or easier installation, a softer compound may be more suitable.

If the application involves high temperature, aggressive chemicals, ozone exposure, outdoor use, steam, or special fluids, FKM, EPDM, silicone, HNBR, or FFKM should be evaluated instead of standard NBR.

NBR is a reliable choice for many oil-resistant sealing applications, but it is not suitable for every working condition.

NBR is not recommended for:

• Long-term outdoor exposure
• Strong ozone or UV environments
• High-temperature chemical systems
• Ketones and some aggressive solvents
• Glycol-based brake fluid systems
• Steam or hot water systems requiring EPDM-level resistance
• Applications requiring strong weather resistance

For these conditions, other materials may perform better:

This material comparison helps buyers avoid wrong material selection, especially for OEM projects, repair orders, and equipment replacement applications.

 Yuefeng supports custom NBR O rings for OEM and industrial sealing orders. Standard sizes and non-standard sizes can be supplied according to drawings, samples, or specific application requirements.

Custom Options：

• Inner diameter
• Cross section
• Hardness
• Color
• Material compound
• Oil-resistant formulation
• Low-temperature compound
• Special tolerance requirement
• Packaging and labeling
• O-ring kits
• Bulk order supply

For custom NBR O rings, buyers can send drawings, samples, or basic size information. If the application condition is special, working medium, temperature, pressure, and installation position should also be provided.

This helps confirm whether standard NBR is suitable or whether another material should be selected.

 

 

For industrial O-ring orders, stable quality is more important than only having the right size. Yuefeng controls NBR O rings from material selection, molding, dimensional inspection, and batch consistency.

Main Control Points：

• Rubber compound confirmation before production
• Hardness testing
• Dimensional inspection for ID, OD, and cross section
• Visual inspection for cracks, burrs, flash, and surface defects
• Compression and sealing performance checks when required
• Batch traceability for repeated orders
• Packing inspection before export

For repeated OEM orders, stable compound control and batch consistency help reduce assembly problems, leakage risks, and replacement costs.

NBR O rings can be supplied in standard and non-standard sizes. Common standards include AS568, ISO 3601, metric sizes, and inch sizes. Custom sizes can also be produced according to drawings or samples.

For buyers who are not sure about the standard size, the following information can be used for quotation:

• ID: inner diameter
• CS: cross section
• OD: outer diameter
• Hardness
• Quantity
• Working medium
• Application type
• Drawing or sample photo

For repair orders or replacement projects, sending the existing O-ring sample or equipment groove size can help confirm the correct size more accurately.

Why Choose Yuefeng NBR O Rings

Yuefeng supplies NBR O rings for industrial sealing, hydraulic systems, pneumatic equipment, automotive parts, pumps, valves, machinery, and replacement applications.

Our supply supports both standard O-ring orders and custom sealing projects. Buyers can choose standard black NBR O rings, special hardness, custom sizes, custom colors, OEM packaging, or O-ring kit arrangements according to project needs.

For distributors, equipment manufacturers, and maintenance suppliers, Yuefeng can provide stable batch supply and customized packaging support for long-term orders.

Get a quote and samples

Send us your NBR O ring size, drawing, sample, hardness requirement, working medium, and quantity. Yuefeng can supply standard and custom NBR O rings for industrial sealing, hydraulic systems, pneumatic equipment, automotive parts, pumps, valves, and OEM sealing projects.

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