HNBR O-Ring
HNBR O-rings can withstand acids, alkalis, and salts at high temperatures, and are capable of operating in lubricant oil and fuel containing highly corrosive additives.
Table of content
- HNBR Material Property
- O-RING Size Calculation
- Working Temperature Range
- Chemical Resistance
- O-Ring Lubrication
- O-Ring Color
- Typical Applications
EPDM Material Property
| Serial | Characteristic | Unit | Test method | Specification | Result |
| 1 | Colour | Black | Black | ||
| 2 | Density | g/cm3 | ISO 2781 | 1.26±0.02 | 1.27 |
| 3 | Hardness | Shore A | ASTM D2240 | 75±5 | 73 |
| 4 | Tensile strength | MPa | ASTM D412 | 15min | 24 |
| 5 | Elongation | % | ASTM D412 | 200min | 243 |
| 6 | Compression set:72h at 150°C | % | ISO 815-1 TypeB | 35max | 22 |
| 7 | TR10 | ℃ | ASTM D746 | -20max | -24 |
Working Temperature Range
Temperature range : –60°C to 150°C
Chemical Resistance
| Chemical | Resistance Rating | Temperature Range | Notes |
|---|---|---|---|
| Mineral Oils | Excellent | Up to 150°C | Highly resistant to most oils, including hydraulic and lubricating oils. |
| Diesel Fuel | Excellent | Up to 150°C | Excellent resistance to aliphatic hydrocarbons. |
| Gasoline/Petroleum | Good | Up to 150°C | Resists standard gasoline; avoid blends with high aromatic or ethanol content. |
| Acids (diluted, e.g., 10% H₂SO₄) | Good | Up to 100°C | Resists weak acids; avoid concentrated or oxidizing acids. |
| Alkalis (e.g., NaOH 30%) | Good | Up to 100°C | Suitable for moderate alkali exposure. |
| Aromatic Hydrocarbons | Fair | Up to 80°C | Limited resistance (e.g., benzene, toluene); avoid prolonged contact. |
| Ethylene Glycol | Excellent | Up to 150°C | Resistant to antifreeze and coolants. |
| Ammonia (aqueous) | Fair | Up to 80°C | Moderate resistance; avoid high concentrations. |
| Chlorinated Solvents | Poor | Up to 60°C | Severe swelling (e.g., dichloromethane, trichloroethylene). |
| Ketones (e.g., Acetone) | Poor | Up to 60°C | Rapid degradation; not recommended. |
| Alcohols (e.g., Methanol) | Good | Up to 120°C | Resistant to short-term exposure. |
| Salt Solutions | Excellent | Up to 150°C | Excellent resistance to brines and saltwater. |
| Ozone/Weathering | Excellent | Up to 150°C | Superior to NBR; resists oxidation and weathering. |
O-RING Size Calculation
The selection of O-rings primarily depends on compression ratio because it directly impacts the sealing performance, durability.
Formula for Compression Ratio
The compression ratio () of an O-ring is calculated using the following equation:
C=(CS−Gd)/CS × 100%
Where:
= Cross-sectional diameter of the O-ring (mm or inches)
= Groove depth (mm or inches)
Acceptable Compression Ratio Guidelines
| Application Type | Recommended Compression Ratio | |
|---|---|---|
| Static Seals | 15% – 30% | |
| Dynamic Seals | 10% – 20% | |
| High-Pressure Seals | 20% – 30% |
O-Ring Lubrication
Surface coatings are applied to O-rings to enhance their performance in demanding applications. The primary purposes include:
Friction Reduction: Minimize assembly force.
Chemical Resistance: Protects against aggressive media (acids, solvents, fuels).
Coating Materials
| Coating Material | Key Properties | Color |
|---|---|---|
| PTFE (Polytetrafluoroethylene) | – Ultra-low friction (μ ≈ 0.05–0.1) – Chemical inertness – Temp range: -60°C to +260°C | Light white |
| Lubricate FP(PFPE based lubricating fluid) | – Low friction – Prevent the O-rings from twisting – Compatible with cleanness requirements – NO impact on the mechanical properties of the rubber | Transparent |
| Molybdenum Disulfide (MoS₂) | – Low friction – Anti-galling | Dark grey |
O-Ring Color
Different color can be chosen for easlier identification.
- Black
- Green
- Red
Typical Applications
- Automotive – Cooling System
- Automotive – HVAC System
- Automotive – Braking System
- Drink Water Industry
- Food Industry
Thanks to contact us to discuss your requirements regarding O-RINGs. We are ready to assist you with fast, reliable support.