Silicone O-Ring
Silicone O-Ring is widely used in medical, food-grade, and high-temperature sealing applications because of its biocompatibility and thermal stability.
Table of content
- Silicone Material Property
- O-RING Size Calculation
- Working Temperature Range
- Chemical Resistance
- O-Ring Lubrication
- O-Ring Color
- Typical Applications
Silicone Material Property
| Property | Test Standard | Typical Value |
| Density | ASTM D792, ISO 2781 | 1.2 g/cm³ |
| Tensile Strength | ASTM D412, ISO 37 | 10 MPa |
| Compression Set (22 hrs @ 150°C) | ASTM D395, ISO 815 | 20% |
| TR10 | ASTM D1329, ISO 2921 | -50°C |
| Elongation at Break | ASTM D412, ISO 37 | 280% |
Working Temperature Range
Temperature range : –60°C to 200°C
Chemical Resistance
| Chemical | Resistance Rating | Temperature Range | Notes |
| Mineral Oils | Poor | Up to 80°C | Swells significantly; avoid prolonged exposure. |
| Diesel Fuel | Poor | Up to 60°C | Severe swelling and loss of mechanical properties. |
| Acids (diluted) | Fair | Up to 100°C | Resists weak acids (e.g., 10% HCl); avoid concentrated or oxidizing acids. |
| Alkalis (e.g., NaOH 10%) | Poor | Up to 60°C | Degrades rapidly; not recommended for alkaline environments. |
| Ethanol | Fair | Up to 80°C | Limited resistance; avoid high concentrations. |
| Ethylene Glycol | Good | Up to 150°C | Suitable for antifreeze/coolant applications. |
| Aromatic Hydrocarbons | Poor | Up to 60°C | Severe swelling (e.g., benzene, toluene). |
| Chlorinated Solvents | Poor | Up to 50°C | Rapid degradation (e.g., dichloromethane, chloroform). |
| Ketones (e.g., Acetone) | Poor | Up to 50°C | Dissolves or swells; avoid entirely. |
| Salt Solutions | Excellent | Up to 200°C | Highly resistant to brines and saltwater. |
| Ozone/UV/Weathering | Excellent | Up to 200°C | Outstanding resistance to oxidation, UV, and weathering. |
| Hot Air | Excellent | Up to 230°C | Stable in dry heat; ideal for high-temperature gaskets. |
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
- White
- Red
Typical Applications
- Eletrical Connector
- Drink Water Industry
- Food Industry
- Heath Care Advice
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