Chemraz 505 vs Kalrez 0040: FFKM Compound Comparison
Verified by Rachel Mayfield, Supply Chain Analyst - April 2026
Chemraz 505 and Kalrez 0040 are both perfluoroelastomer (FFKM) compounds used in chemical, refinery, and process applications. Chemraz 505 vs Kalrez 0040 They share similar chemistry but differ on temperature ceiling, hardness, and intended service. This page compares the two side-by-side and explains when to specify each.
Side-by-side comparison
| Property | Chemraz 505 | Kalrez 0040 |
|---|---|---|
| Manufacturer | Greene Tweed | DuPont (Chemours) |
| Compound | 505 | 0040 |
| Maximum continuous temp | 230°C | 250°C |
| Minimum temp | -34°C | -25°C |
| Hardness | 75 Shore A | 70 Shore A |
| Colour | Black | Black |
| Typical applications | Aerospace, refrigeration, cold chemical service | Aerospace fuels, low-temp chemical service |
When to specify Chemraz 505
Chemraz 505 suits aerospace and similar service. Continuous temperature window is -34°C to 230°C, hardness 75 Shore A. Manufactured by Greene Tweed.
When to specify Kalrez 0040
Kalrez 0040 suits aerospace fuels and similar service. Continuous temperature window is -25°C to 250°C, hardness 70 Shore A. Manufactured by DuPont (Chemours).
Key differences
- Temperature ceiling: Kalrez 0040 runs 20°C hotter (250°C vs 230°C). Specify the higher-rated compound when continuous service is above 230°C.
- Hardness: Chemraz 505 is 75 Shore A; Kalrez 0040 is 70 Shore A. Harder compounds resist extrusion at high pressure but seal less compliantly on imperfect surfaces.
- Manufacturer: Chemraz 505 is from Greene Tweed; Kalrez 0040 is from DuPont (Chemours). Lead time and UK availability vary by brand.
- Cost: FFKM pricing varies by manufacturer, batch size, and stock position. Both compounds are at the premium end of elastomer pricing (£30 to £500+ per O-ring depending on size).
Get a UK quote on either compound
Related pages
Frequently Asked Questions
Can I substitute Chemraz 505 for Kalrez 0040?
Yes, Chemraz 505 and Kalrez 0040 are both FFKM compounds with overlapping chemical compatibility. Verify your specific fluid against both manufacturers' compatibility tables before substitution. Temperature window, hardness, and certifications may differ.
Which is hotter: Chemraz 505 or Kalrez 0040?
Kalrez 0040 has a higher continuous temperature ceiling (250°C vs 230°C, a 20°C difference).
Which costs less: Chemraz 505 or Kalrez 0040?
FFKM compound pricing depends on manufacturer, batch size, certifications, and current stock position rather than headline brand. Both compounds are at the premium end of elastomer pricing. Get current UK quotes on both before specifying.
Where can I buy Chemraz 505 or Kalrez 0040 in the UK?
Both compounds are supplied in the UK by independent FFKM seal specialists carrying multiple manufacturer lines. Lead time is typically 2-5 working days for stock BS 1806 / AS568 sizes, 4-8 weeks for custom-moulded sizes.