Chemraz 526 vs Kalrez 7075: FFKM Compound Comparison
Verified by Rachel Mayfield, Supply Chain Analyst - April 2026
Chemraz 526 and Kalrez 7075 are both perfluoroelastomer (FFKM) compounds used in chemical, refinery, and process applications. Chemraz 526 vs Kalrez 7075 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 526 | Kalrez 7075 |
|---|---|---|
| Manufacturer | Greene Tweed | DuPont (Chemours) |
| Compound | 526 | 7075 |
| Maximum continuous temp | 327°C | 327°C |
| Minimum temp | -10°C | 0°C |
| Hardness | 75 Shore A | 75 Shore A |
| Colour | Off-White | White-Cream |
| Typical applications | Semiconductor processing, wet/dry etch, plasma | Semiconductor wafer fabrication, plasma etch, CVD chambers |
When to specify Chemraz 526
Chemraz 526 suits semiconductor processing and similar service. Continuous temperature window is -10°C to 327°C, hardness 75 Shore A. Manufactured by Greene Tweed.
When to specify Kalrez 7075
Kalrez 7075 suits semiconductor wafer fabrication and similar service. Continuous temperature window is 0°C to 327°C, hardness 75 Shore A. Manufactured by DuPont (Chemours).
Key differences
- Temperature ceiling: Kalrez 7075 runs 0°C hotter (327°C vs 327°C). Specify the higher-rated compound when continuous service is above 327°C.
- Hardness: Both are 75 Shore A, so groove design and squeeze percentage are interchangeable.
- Manufacturer: Chemraz 526 is from Greene Tweed; Kalrez 7075 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 526 for Kalrez 7075?
Yes, Chemraz 526 and Kalrez 7075 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 526 or Kalrez 7075?
Kalrez 7075 has a higher continuous temperature ceiling (327°C vs 327°C, a 0°C difference).
Which costs less: Chemraz 526 or Kalrez 7075?
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 526 or Kalrez 7075 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.