O-Ring Materials Guide
Choose the right O-ring material for your application. Our comprehensive guide covers temperature ranges, chemical compatibility, hardness options, and typical applications for all major elastomer types.
Material Selection Quick Reference
| Material | Continuous Temp | Short-term Temp | Hardness Range | Chemical Resistance | Cost Level |
|---|---|---|---|---|---|
| Nitrile (NBR) | -40°F to +212°F | -40°F to +248°F (-40°C to +120°C) | 40-95 Shore A | Oils, fuels, hydraulic fluids | $ - Economy |
| Viton (FKM) | -4°F to +392°F (-20°C to +200°C) | -4°F to +428°F (-20°C to +220°C) | 65-95 Shore A | Acids, solvents, chemicals | $$$ - Premium |
| EPDM | -67°F to +275°F (-55°C to +135°C) | -67°F to +302°F (-55°C to +150°C) | 50-90 Shore A | Water, steam, ozone, weather | $$ - Mid-range |
| Silicone (VMQ) | -67°F to +450°F (-55°C to +232°C) | -67°F to +482°F (-55°C to +250°C) | 30-90 Shore A | Extreme temps, food grade | $$$ - Premium |
| HNBR | -40°F to +275°F (-40°C to +135°C) | -40°F to +302°F (-40°C to +150°C) | 70-95 Shore A | High temp oils, automotive | $$$ - Premium |
Material Categories
🏭 General Purpose Materials
Cost-effective solutions for standard industrial applications
- Nitrile (NBR) - Oil and fuel resistance
- EPDM - Water and weather resistance
- Neoprene (CR) - General purpose, moderate chemicals
- SBR - Water applications, low cost
🌡️ High Performance Materials
Advanced elastomers for demanding environments
- Viton (FKM) - Chemical and high temperature
- Silicone (VMQ) - Extreme temperatures
- HNBR - High temperature oil resistance
- Perfluoroelastomer (FFKM) - Ultimate chemical resistance
Most Popular O-Ring Materials
Nitrile (NBR) O-Rings
Temperature: -40°F to +248°F (-40°C to +120°C)
Best For: Oil, fuel, hydraulic applications
Most economical choice for petroleum-based fluids. Excellent oil swell resistance and good mechanical properties.
Viton (FKM) O-Rings
Temperature: -4°F to +428°F (-20°C to +220°C)
Best For: Chemical, automotive, aerospace
Superior chemical resistance and high temperature performance. Industry standard for demanding applications.
EPDM O-Rings
Temperature: -67°F to +302°F (-55°C to +150°C)
Best For: Water, steam, outdoor applications
Excellent weather and ozone resistance. Perfect for water systems and outdoor equipment.
Material Selection by Application
| Application | Primary Material | Alternative | Key Considerations | Typical Hardness |
|---|---|---|---|---|
| Hydraulic Systems | NBR 70-90A | HNBR 80A | Oil compatibility, pressure rating | 80-90 Shore A |
| Chemical Processing | FKM 75-90A | FFKM 80A | Chemical resistance chart required | 75-85 Shore A |
| Food/Beverage | EPDM 70A | Silicone 70A | FDA/USP compliance, taste/odor | 70-80 Shore A |
| Automotive Engine | FKM 90A | HNBR 90A | High temp, oil/fuel resistance | 85-95 Shore A |
| Water Treatment | EPDM 70A | NBR 70A | Chlorine resistance, NSF approval | 70-80 Shore A |
Temperature Capability Chart
| Material | Low Temp (°F) | Low Temp (°C) | High Temp (°F) | High Temp (°C) | Short-Term Max |
|---|---|---|---|---|---|
| Silicone (VMQ) | -67°F (-55°C) | +450°F (+232°C) | +482°F (+250°C) | ||
| Viton (FKM) | -4°F (-20°C) | +392°F (+200°C) | +428°F (+220°C) | ||
| HNBR | -40°F (-40°C) | +275°F (+135°C) | +302°F (+150°C) | ||
| EPDM | -67°F (-55°C) | +275°F (+135°C) | +302°F (+150°C) | ||
| Nitrile (NBR) | -40°F (-40°C) | +212°F (+100°C) | +248°F (+120°C) |
Chemical Resistance Overview
🛡️ Excellent Chemical Resistance
- Viton (FKM): Most acids, aromatic hydrocarbons, chlorinated solvents
- FFKM: Nearly universal chemical resistance
- EPDM: Alkaline solutions, hot water, steam
- PTFE: Aggressive chemicals, extreme pH
⚠️ Limited Chemical Resistance
- NBR: Avoid ketones, esters, ozone
- Silicone: Avoid fuels, oils, concentrated acids
- Natural Rubber: Avoid oils, ozone, UV exposure
- Neoprene: Avoid strong acids, aromatic hydrocarbons
Shore A Hardness Selection Guide
| Shore A Hardness | Feel/Flexibility | Best Applications | Pressure Rating | Common Sizes |
|---|---|---|---|---|
| 60-70A | Soft, flexible | Low pressure, food grade, face seals | Up to 150 PSI | Large cross-sections, face seal applications |
| 70-80A | Medium, general purpose | Standard hydraulic, pneumatic systems | Up to 1,500 PSI | Most AS568 sizes, general purpose |
| 80-90A | Firm, high strength | High pressure hydraulics, wear resistance | Up to 5,000 PSI | Small cross-sections, high pressure |
| 90+ Shore A | Hard, rigid | Extreme pressure, backup rings | Above 5,000 PSI | Specialized high-pressure applications |
Material Certifications & Standards
🏭 Industrial Standards
- ASTM D2000 - Automotive rubber
- SAE AMS-R - Aerospace materials
- MIL-R - Military specifications
- ISO 3601 - O-ring standards
🍎 Food & Medical
- FDA Title 21 CFR 177.2600
- USP Class VI certification
- 3A Dairy Standards
- EU 1935/2004 food contact
🌍 Environmental
- RoHS compliance
- REACH regulation
- NSF/ANSI 61 drinking water
- WRAS approved materials
🧪 Interactive Material Selection Wizard
Answer a few questions about your application to get personalized O-ring material recommendations with engineering rationale.
What is your operating temperature range?
Common Temperature Ranges:
What chemicals or fluids will the O-ring contact?
Select Primary Chemical Category:
What type of sealing application?
Operating Pressure:
Any special requirements or certifications needed?
📋 Regulatory Compliance:
🏭 Industry Standards:
🔬 Special Properties:
Cost Consideration:
🎯 Material Recommendations
Need Expert Material Selection Assistance?
Our technical team can help identify the optimal O-ring material for your specific application requirements.
Request Material Recommendation Speak with EngineerO-Ring Materials FAQ
Expert answers to common questions about o ring materials, applications, and selection criteria.
🔥 What are Viton O-Rings?
Viton o rings are fluoroelastomer (FKM) seals offering excellent chemical resistance and high temperature performance. What is viton o rings used for? They're ideal for automotive, aerospace, and chemical processing applications requiring resistance to fuels, oils, and extreme temperatures up to 400°F.
- Temperature range: -20°F to 400°F
- Excellent fuel and oil resistance
- Superior chemical compatibility
- Automotive and aerospace applications
⚖️ HNBR vs NBR O-Rings
HNBR (Hydrogenated Nitrile) offers enhanced temperature and ozone resistance compared to standard NBR (Nitrile Butadiene Rubber) o rings.
⛽ Fuel Resistant O-Ring Materials
For fuel system applications, specific elastomers provide optimal resistance to gasoline, diesel, and alternative fuels.
- Viton FKM: Excellent for all fuel types including ethanol blends
- NBR: Good for petroleum-based fuels
- FFKM: Ultimate resistance for extreme fuel applications
- HNBR: Enhanced performance in biodiesel applications
🔍 How to Identify O-Ring Material
Material identification involves testing physical properties, chemical resistance, and temperature capabilities.
- Hardness testing (Shore A durometer)
- Temperature resistance evaluation
- Chemical compatibility testing
- Visual inspection and color analysis
Need Material Selection Guidance?
Our materials engineers provide free consultation to help select the optimal elastomer for your specific application requirements.