FFKM O-Ring
FFKM (Perfluoroelastomer) is a high-performance elastomer characterized by exceptional resistance to extreme temperatures (above 300°C), aggressive chemicals, and plasma exposure, owing to its fully fluorinated molecular structure.
Table of content
- FFKM Material Property
- O-RING Size Calculation
- Working Temperature Range
- Chemical Resistance
- O-Ring Lubrication
- O-Ring Color
- Typical Applications
FFKM Material Property
| Property | Typical Value |
| Temperature Range | -25°C to +327°C (short-term up to 330°C) |
| Tensile Strength | 15 MPa |
| Elongation at Break | 200% |
| Compression Set (72h @ 200°C) | 20% |
| Thermal Stability | Excellent (no degradation below 300°C) |
Working Temperature Range
Temperature range : –20°C to 320°C
Chemical Resistance
| Chemical | Resistance Level | Notes |
|---|---|---|
| Sulfuric Acid (98%) | Excellent | Full immersion up to 200°C |
| Hydrochloric Acid (37%) | Excellent | No swelling even at high temps |
| Hydrofluoric Acid (48%) | Excellent | Superior to most elastomers |
| Sodium Hydroxide (50%) | Excellent | Resists strong alkalis |
| Chlorine Gas | Excellent | No permeation issues |
| Acetone | Excellent | Minimal swelling |
| Methanol/Ethanol | Excellent | No chemical attack |
| Hydrogen Peroxide (30%) | Good | Avoid prolonged exposure >100°C |
| Ammonia (Anhydrous) | Good | Limited to moderate concentrations |
| Benzene | Good | Short-term exposure only |
| Diesel/Kerosene | Excellent | No degradation |
| Plasma Etching Gases | Excellent | Critical in semiconductor tools |
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
- Blue
- Transparent
Typical Applications
- Semiconductor Industry
- Pharmaceutical systems
- Chemical processing
- Oil and gas Industry
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