O-rings are critical sealing components used across virtually every industry. Selecting the right material is essential for reliable sealing performance, longevity and safety.
Common O-Ring Materials
EPDM (Ethylene Propylene Diene Monomer)
- Temperature Range: -40°C to +150°C
- Strengths: Excellent resistance to hot water, steam, ozone and weathering. Good for brake fluids and phosphate ester hydraulic fluids.
- Limitations: Not suitable for petroleum oils, fuels or most hydrocarbons.
- Applications: Automotive cooling systems, HVAC, plumbing, brake systems.
NBR (Nitrile Butadiene Rubber)
- Temperature Range: -30°C to +100°C
- Strengths: Excellent resistance to petroleum oils, fuels and hydraulic fluids. Good abrasion resistance.
- Limitations: Poor resistance to ozone, weathering and polar solvents.
- Applications: Hydraulic systems, fuel systems, automotive engines, oil and gas.
FKM (Fluorocarbon / Viton)
- Temperature Range: -20°C to +200°C
- Strengths: Excellent chemical resistance, high temperature capability, good resistance to oils and fuels.
- Limitations: Higher cost, poor resistance to ketones and esters.
- Applications: Aerospace, chemical processing, high-temperature hydraulic systems.
Selection Guidelines
- Identify the fluid media and check chemical compatibility charts.
- Determine the operating temperature range.
- Consider pressure requirements and potential extrusion risks.
- Evaluate environmental factors (ozone, UV, weathering).
- Balance performance requirements with cost considerations.
Conclusion
Proper O-ring material selection requires understanding the application environment, fluid compatibility and performance requirements. When uncertain, consult material compatibility charts or sealing specialists.