O-Ring Material Selection Guide
Choose the right elastomer material based on your application's temperature range and chemical compatibility.
| Code | Material | Temp Range | Best For |
|---|---|---|---|
| NBR | Nitrile (Buna-N) | -40°C to +120°C | Petroleum oils, hydraulic fluids |
| FKM | Viton® (Fluorocarbon) | -20°C to +200°C | Fuels, chemicals, high heat |
| EPDM | Ethylene Propylene | -50°C to +150°C | Water, steam, brake fluids |
| VMQ | Silicone | -60°C to +230°C | Extreme temps, food grade |
| FFKM | Perfluoroelastomer | -25°C to +320°C | Extreme chemicals, aerospace |
| CR | Neoprene | -40°C to +100°C | Refrigerants, weather sealing |
Viton® O-Rings (FKM/FPM)
Viton® is DuPont's trade name for fluorocarbon rubber (FKM). It offers exceptional resistance to heat, oils, fuels, and chemicals, making it the premium choice for demanding applications.
Temperature Range
-20°C to +200°C (-4°F to +392°F). Special compounds can handle up to 250°C.
Chemical Compatibility
- ✅ Petroleum oils and fuels (including gasoline, diesel, bio-diesel)
- ✅ Aromatic hydrocarbons
- ✅ Chlorinated solvents
- ✅ Mineral acids (dilute)
- ❌ Ketones (acetone, MEK)
- ❌ Amines and ammonia
- ❌ Hot water and steam (use EPDM instead)
Common Applications
Automotive fuel systems, aircraft fuel systems, chemical processing, oil field equipment, aerospace.
Nitrile O-Rings (NBR/Buna-N)
Nitrile (also called Buna-N or NBR) is the most widely used O-ring material due to its excellent balance of properties and low cost. It's the default choice for petroleum-based applications.
Temperature Range
-40°C to +120°C (-40°F to +248°F). Some high-temp grades extend to 135°C.
Chemical Compatibility
- ✅ Petroleum oils and greases
- ✅ Hydraulic fluids (mineral oil based)
- ✅ Water (limited time)
- ✅ Silicone greases and oils
- ❌ Ozone and UV (poor weather resistance)
- ❌ Ketones and esters
- ❌ Brake fluids (use EPDM)
Common Applications
Hydraulic systems, automotive engines, pneumatic equipment, machine tools, general industrial sealing.
EPDM O-Rings
EPDM (Ethylene Propylene Diene Monomer) excels in water, steam, and brake fluid applications where Nitrile fails. It has excellent weather and ozone resistance.
Temperature Range
-50°C to +150°C (-58°F to +302°F). Special grades handle -60°C.
Chemical Compatibility
- ✅ Water (hot and cold)
- ✅ Steam
- ✅ Glycol-based brake fluids (DOT 3, DOT 4)
- ✅ Phosphate ester hydraulic fluids (Skydrol)
- ✅ Ozone and UV (outdoor use)
- ❌ Petroleum oils (will swell and fail)
- ❌ Mineral oil-based lubricants
Common Applications
Brake systems, water pumps, steam systems, washing machines, outdoor applications, food/beverage.
Silicone O-Rings (VMQ)
Silicone offers the widest temperature range of common elastomers and is inherently food-safe, making it ideal for food processing and medical applications.
Temperature Range
-60°C to +230°C (-76°F to +446°F). Some grades handle -100°C to +300°C.
Chemical Compatibility
- ✅ Ozone and UV (excellent weather resistance)
- ✅ Many dilute acids and bases
- ✅ Food contact (FDA approved grades)
- ❌ Petroleum oils (poor resistance)
- ❌ Steam (short life)
- ❌ Concentrated acids
Common Applications
Food processing, medical devices, aerospace, high/low temperature applications, static seals.
Note: Silicone has low tear and abrasion resistance. Use only in static or low-speed dynamic applications.
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