Worried your seals might fail in extreme heat? The wrong sealing material can degrade, crack, or melt under high-temperature conditions—leading to system leaks and equipment damage.
The best seal materials for high-temperature applications include FKM (Viton®), PTFE, silicone, and graphite, depending on the exact temperature range, media, and pressure involved.
Let’s compare these materials and help you find the right one for sealing under heat stress.
What Is Considered "High Temperature" for Sealing?
Not sure if your application qualifies as high temp?
In sealing applications, “high temperature” typically refers to operating temperatures above +150°C and can exceed +300°C in industrial systems like engines, turbines, or chemical reactors.
✅ Common High-Temperature Zones:
- Internal combustion engines
- Turbines and exhaust systems
- Heat exchangers
- Chemical reactors and process piping
- Autoclaves, sterilizers, ovens
Top Seal Materials for High-Temperature Use
Here’s a breakdown of the best sealing materials based on temperature, chemical resistance, and sealing strength.
| Material | Max Temp (°C) | Chemical Resistance | Compression Set | Application Examples |
|---|---|---|---|---|
| ✅ PTFE (Teflon®)1 | ~260 | Excellent ✅ | Poor ⚠️ | Valves, gaskets, chemical processing |
| ✅ FKM (Viton®)2 | ~230 | Excellent ✅ | Excellent ✅ | Engines, fuel systems, industrial pumps |
| ✅ Silicone | ~200–250 | Moderate ⚠️ | Moderate ⚠️ | Food processing, medical, HVAC static seals |
| ✅ Graphite3 | ~500–550 | Excellent ✅ | N/A (rigid) | Flange gaskets, steam lines, refinery piping |
| ✅ Kalrez® (FFKM) | ~327 | Outstanding ✅ | Excellent ✅ | Semiconductor, pharma, aggressive chemical use |
When to Choose FKM (Viton®)
Need a high-performance elastomer for heat and oil resistance?
FKM is ideal for dynamic seals in engines, pumps, and valves exposed to heat and fuel. It resists compression set and chemical degradation.
✅ Best For:
- Engine oil seals
- Fuel injection components
- Industrial equipment with mineral oil or gas exposure
- Operating temps up to +230°C
When to Choose PTFE
Worried about aggressive chemicals and dry heat?
PTFE (Teflon®) offers the highest chemical resistance and can handle dry heat and steam up to 260°C—but it lacks elasticity.
✅ Best For:
- Static gaskets in pipes and tanks
- Semiconductor and chemical plant sealing
- High-purity or aggressive chemical environments
- Steam applications
⚠️ PTFE is rigid and should be used where no dynamic movement or sealing flex is required.
When to Use Silicone4 Seals
Working in high heat with FDA or medical-grade requirements?
Silicone offers excellent thermal stability and is ideal for static seals where flexibility and safety are key.
✅ Use Silicone When:
- Temperature is below 250°C
- The seal must be food- or medical-grade
- Application involves static sealing or light pressure
- Good UV/ozone/weather resistance is required
Avoid silicone in fuel or oil exposure—it will swell or degrade.
Graphite and Kalrez®5 for Extreme Industrial Heat
Need a sealing solution beyond 300°C?
Graphite gaskets and perfluoroelastomers like Kalrez® are used in the most extreme environments where standard elastomers fail.
✅ Use Graphite or Kalrez® For:
- Superheated steam (graphite)
- Chemical reactors (Kalrez®)
- Semiconductor manufacturing (Kalrez®)
- High-pressure flanged joints
Summary Table: Best High-Temperature Seal Materials
| Application Condition | Recommended Material ✅ |
|---|---|
| Engine oil/fuel systems | FKM (Viton®) |
| Aggressive chemicals + heat | PTFE or Kalrez® |
| Static seals in hot ovens | Silicone |
| Steam lines or flanged joints | Graphite |
| Cleanroom/pharma/high purity | Kalrez® |
Conclusion
For most high-temperature elastomeric seals, FKM offers the best balance of heat, oil, and chemical resistance. For static sealing or extreme chemical/heat exposure, PTFE, graphite, or Kalrez® are superior choices. Match the material to your system’s heat, pressure, and media to ensure long-term sealing success.
🔥 Need Custom High-Temp Seals?
Contact Julong Rubber or Request a Quote for high-temperature sealing materials including FKM, PTFE, and more.
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Explore the advantages of PTFE in high-temperature settings, including its chemical resistance and durability. ↩
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Learn why FKM is a top choice for high-temperature seals, especially in engines and fuel systems. ↩
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Discover the versatility of graphite seals in extreme temperatures and their applications in various industries. ↩
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Learn about silicone's thermal stability and flexibility, making it ideal for food and medical applications, ensuring safety and performance. ↩
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Explore the advantages of Kalrez® for extreme conditions, ensuring reliability in critical applications. ↩
