NBR O-Rings
High-performance Nitrile Butadiene Rubber (NBR) O-rings engineered for superior oil resistance and cost-effectiveness. The industry standard for automotive and industrial applications requiring excellent compatibility with petroleum oils, fuels, and hydraulic fluids.
NBR Properties & Specifications
📊 Physical Properties
| Material Type | Nitrile Butadiene Rubber (NBR) |
| Continuous Temperature | -40°C to 120°C (-40°F to 248°F) |
| Short-term Temperature | Up to 135°C (275°F) |
| Hardness Range | 70-90 Shore A |
| Tensile Strength | 10-25 MPa (1450-3625 psi) |
| Elongation at Break | 100-600% |
🎨 Available Options
Temperature Performance
| Temperature Range | Fahrenheit | Celsius | Duration | Performance Notes |
|---|---|---|---|---|
| Continuous Operating | -40°F to +248°F | -40°C to +120°C | Unlimited | Optimal performance range |
| Short-term Exposure | Up to +275°F | Up to +135°C | Up to 48 hours | Emergency/startup conditions |
| Brittle Point | -60°F to -65°F | -51°C to -54°C | N/A | Becomes rigid, may crack |
Chemical Compatibility
✅ Excellent Resistance
- Petroleum Oils and Fuels
- Hydraulic Fluids (mineral oil based)
- Aliphatic Hydrocarbons
- Vegetable Oils and Animal Fats
- Dilute Acids and Alkalis
- Salt Water
⚠️ Poor/No Resistance
- Ozone and Weather Exposure
- Ketones and Esters
- Aromatic Hydrocarbons
- Chlorinated Hydrocarbons
- Strong Oxidizing Agents
| Chemical/Fluid | Concentration | Temperature | Rating | Notes |
|---|---|---|---|---|
| Motor Oil (SAE 30) | 100% | 120°C | Excellent | Ideal for automotive applications |
| Diesel Fuel | 100% | Room Temp | Excellent | Perfect for fuel systems |
| Hydraulic Oil (Mineral) | 100% | 80°C | Excellent | Industry standard |
| Gasoline | 100% | Room Temp | Excellent | Automotive fuel systems |
| Propane | 100% | Room Temp | Excellent | LPG applications |
| Acetone | 100% | Room Temp | Poor | Causes severe swelling |
| Benzene | 100% | Room Temp | Poor | Use FKM instead |
| Steam | 100% | Above 100°C | Poor | Use EPDM for steam |
Rating Scale: Excellent = No effect, Good = Slight effect acceptable, Fair = Moderate effect, Poor = Severe effect, not recommended
Common Applications
🏭 Industrial Applications
- Hydraulic System Seals
- Oil & Gas Equipment
- Fuel System Components
- Machine Tool Sealing
- Pumps and Compressors
🚗 Automotive Applications
- Engine Oil System Seals
- Fuel Injection Components
- Transmission Seals
- Brake System Components
- Power Steering Systems
🏠 Consumer Applications
- Garden Hose Fittings
- Plumbing Seals
- Lawn Mower Engines
- Small Engine Carburetors
- Appliance Gaskets
NBR Compound Grades & Acrylonitrile Content
| Grade | ACN Content | Oil Resistance | Low Temp Flexibility | Typical Applications |
|---|---|---|---|---|
| Low ACN (18-25%) | 18-25% | Fair | Excellent | Cold weather, low oil contact |
| Medium ACN (25-35%) | 25-35% | Good | Good | General automotive, hydraulics |
| Medium-High ACN (35-42%) | 35-42% | Very Good | Fair | Fuel systems, oil seals |
| High ACN (42-50%) | 42-50% | Excellent | Poor | High oil content, aggressive fuels |
Selection Guide: Higher acrylonitrile content increases oil resistance but reduces low-temperature flexibility. Choose the grade that best matches your application requirements.
Automotive Industry Applications
🚗 Engine Systems
NBR O-rings are the automotive industry standard for engine oil sealing applications:
- Engine Oil Pan Drain Plugs: Withstand engine oil temperatures up to 120°C
- Oil Filter Housing: Seal engine oil under pressure and temperature cycling
- Valve Cover Gaskets: Multi-piece designs using NBR O-ring sealing elements
- Oil Pump Seals: Dynamic sealing in high-pressure oil circulation systems
- Crankcase Ventilation: PCV system sealing in contact with oil vapors
Performance: NBR provides 50,000+ mile service life in typical automotive engine applications.
⛽ Fuel Systems
Critical sealing components for automotive fuel delivery and injection systems:
- Fuel Injector O-rings: High-precision sealing for gasoline and diesel injection
- Fuel Rail Connections: High-pressure fuel distribution sealing
- Fuel Tank Sending Units: Immersion service in gasoline and ethanol blends
- Fuel Pump Assemblies: Electric fuel pump sealing components
- Fuel Line Connections: Quick-connect fittings and threaded connections
Compatibility: Suitable for E10 ethanol blends commonly used in modern gasoline.
🔧 Transmission & Power Systems
- Automatic transmission fluid seals
- Manual transmission drain plugs
- Power steering pump seals
- Differential housing seals
- Transfer case components
🛞 Brake & Hydraulic Systems
- Brake caliper piston seals
- Master cylinder components
- Brake line connections
- Hydraulic clutch systems
- ABS module sealing
🌡️ Cooling & Climate Systems
- Radiator drain plug seals
- Thermostat housing gaskets
- Water pump connections
- A/C system O-rings (limited use)
- Heater core connections
Industrial Applications & Performance Data
🏭 Manufacturing & Processing
NBR O-rings excel in industrial manufacturing environments:
- Machine Tool Hydraulics: CNC machine hydraulic systems operating at 3000+ PSI
- Industrial Compressors: Air and gas compression systems up to 120°C
- Pneumatic Cylinders: Rod and piston sealing in automated manufacturing
- Lubricating Systems: Centralized lubrication for heavy machinery
- Process Equipment: Chemical processing with compatible fluids
Service Life: Industrial NBR seals typically achieve 2-5 years continuous operation.
🛢️ Oil & Gas Applications
Critical sealing solutions for petroleum industry equipment:
- Wellhead Equipment: Surface equipment sealing for crude oil contact
- Pipeline Components: Flanged connections and valve sealing
- Refinery Processing: Distillation and separation equipment seals
- Tank Farm Systems: Storage tank connections and transfer equipment
- Pumping Stations: Centrifugal and positive displacement pump seals
Temperature Rating: Petroleum applications typically operate 60-100°C continuous.
Advanced Technical Specifications
| Property | Test Method | 70 Shore A | 80 Shore A | 90 Shore A |
|---|---|---|---|---|
| Tensile Strength (MPa) | ASTM D412 | 15-20 | 18-25 | 20-30 |
| Elongation at Break (%) | ASTM D412 | 300-600 | 200-400 | 100-300 |
| Compression Set (%) at 100°C, 22 hrs | ASTM D395 Method B | 15-30 | 12-25 | 10-20 |
| Tear Resistance (kN/m) | ASTM D624 | 25-40 | 30-50 | 35-60 |
| Volume Swell in IRM 903 Oil (%) | ASTM D471 | 10-20 | 8-15 | 5-12 |
Cost-Effectiveness & Economic Benefits
💰 Economic Advantages
NBR O-rings provide exceptional value for petroleum-based applications:
- Low Material Cost: 50-70% less expensive than specialty elastomers
- Wide Availability: Standard sizes readily available from multiple suppliers
- Proven Performance: Decades of successful use reduces design risk
- Easy Processing: Standard molding equipment and techniques
- Inventory Efficiency: Single material covers many applications
Cost Comparison Example (Per O-ring):
| Material | Automotive Grade | Industrial Grade |
|---|---|---|
| NBR | $0.25-0.75 | $0.50-1.50 |
| FKM/Viton | $2.00-6.00 | $4.00-12.00 |
| FFKM | $15.00-50.00 | $25.00-100.00 |
📈 Performance Optimization
- ACN Selection: Match acrylonitrile content to oil resistance requirements
- Hardness Optimization: 70A for flexibility, 90A for pressure resistance
- Antioxidant Packages: Extended service life in high-temperature applications
- Carbon Black Loading: UV protection for outdoor applications
- Plasticizer Selection: Low-temperature performance enhancement
- Cure System Optimization: Sulfur vs. peroxide curing for specific properties
- Quality Control: Batch testing ensures consistent performance
- Application Engineering: Proper groove design maximizes seal life
Available AS568 Sizes in NBR
| AS568 Size | ID (inches) | CS (inches) | OD (inches) | 70A Price Range | 80A Price Range |
|---|---|---|---|---|---|
| AS568-214 | 0.739 | 0.070 | 0.879 | $2-4 | $3-6 |
| AS568-110 | 0.489 | 0.070 | 0.629 | $1-2 | $2-3 |
| AS568-325 | 1.475 | 0.070 | 1.615 | $4-7 | $6-10 |
| AS568-030 | 1.112 | 0.139 | 1.390 | $5-8 | $7-12 |
| AS568-012 | 0.301 | 0.070 | 0.441 | $1-2 | $2-3 |
* Prices shown are per piece for quantities 1-99. Volume discounts available for larger quantities.
Installation & Handling Tips
🔧 Installation Best Practices
- Clean groove thoroughly before installation
- Lubricate with compatible lubricant
- Avoid sharp edges during installation
- Check for proper compression (typically 15-25%)
- Verify groove dimensions match AS568 standards
📦 Storage & Handling
- Store in cool, dark, dry environment
- Avoid exposure to UV light and ozone
- Keep away from sharp objects
- Rotate stock using FIFO method
- Shelf life: 10 years when properly stored
- Store away from ozone sources and UV light
Common Issues & Solutions
| Problem | Possible Cause | Solution | Prevention |
|---|---|---|---|
| Premature hardening | Excessive temperature or ozone | Replace with higher temp material | Check operating temperature limits |
| Swelling | Chemical incompatibility | Switch to chemically resistant material | Review chemical compatibility chart |
| Extrusion damage | Excessive pressure or clearance | Use harder durometer or backup ring | Design proper groove clearances |
| Surface cracking | Ozone, UV, or flexing | Use ozone-resistant material | Protect from environmental exposure |
Complete Your NBR Solution
📏
1. Select Size
Find the right AS568 dash number or use our groove calculator for your automotive or hydraulic application.
🔧
2. Verify Application
Confirm oil compatibility and temperature requirements for automotive or industrial use.
💰
3. Get Quote
Request competitive pricing for cost-effective NBR o-rings with fast delivery.
Need Higher Performance?
For extreme temperatures or aggressive chemicals, consider upgrading from NBR to advanced elastomers.
Need NBR O-Rings?
Get a quote for NBR O-rings in any AS568 size or custom dimensions.
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