Simriz SZ481 FFKM O-Ring: Compound, Equivalents, UK Suppliers
Verified by Rachel Mayfield, Supply Chain Analyst - April 2026
Simriz SZ481 is a 75 Shore A perfluoroelastomer (FFKM) manufactured by Freudenberg-NOK. It seals continuously to 230°C and is specified for general chemical process and similar service. Chemical-grade FFKM, marketed as Kalrez 6375 equivalent for sub-230C.
Specifications
| Property | Value |
|---|---|
| Compound | SZ481 |
| Manufacturer | Freudenberg-NOK |
| Maximum continuous temperature | 230°C |
| Minimum temperature | -10°C |
| Hardness | 75 Shore A |
| Colour | Black |
| Material family | Chemical-grade FFKM, marketed as Kalrez 6375 equivalent for sub-230C |
Where Simriz SZ481 is used
Simriz SZ481 is specified for: General chemical process, pharma.
Simriz SZ481 equivalents from other FFKM manufacturers
If Simriz SZ481 isn't available, these compounds from competing manufacturers have similar chemistry and operating windows. Always verify against your actual fluid and temperature before substitution.
| Equivalent compound | Manufacturer | Max temp | Hardness | Direct match |
|---|---|---|---|---|
| Kalrez 6375 | DuPont (Chemours) | 275°C | 75 Shore A | approx |
| Chemraz 555 | Greene Tweed | 240°C | 75 Shore A | ✓ |
Available O-ring sizes
Simriz SZ481 is supplied in:
- BS 1806 sizes: BS001 to BS932 (UK / EU standard, imperial-origin metric)
- AS568 sizes: -001 to -932 (US standard, dimensionally identical to BS 1806)
- ISO 3601 sizes: metric IDs from 2 mm to 670 mm with cross-sections 1.0 mm to 7.0 mm
- JIS B 2401: P, G, S series (Japanese OEM equipment)
- Custom / non-standard: built-to-print for OEM applications
For a list of sizes commonly stocked in the UK, see the BS 1806 size chart, ISO 3601 metric chart, or contact a UK seal specialist below.
UK availability
Simriz SZ481 is supplied in the UK by FFKM specialists carrying multiple manufacturer lines. Lead time is typically 2-5 working days for stock sizes, 4-8 weeks for custom-moulded sizes. Use the form below to get a quote from a UK FFKM specialist.
References
- Freudenberg-NOK — Manufacturer
- ISO 3601 O-ring sizes
- BS 1806
Frequently Asked Questions
What is Simriz SZ481 used for?
Simriz SZ481 is a 75 Shore A FFKM (perfluoroelastomer) compound from Freudenberg-NOK. It is used in General chemical process, pharma. Continuous service temperature: -10°C to 230°C.
What is the temperature rating of Simriz SZ481?
Simriz SZ481 has a continuous service temperature range of -10°C to 230°C. Short-term excursions above the maximum are possible but degrade service life.
What is the equivalent of Simriz SZ481?
Direct equivalents to Simriz SZ481 include: Kalrez 6375, Chemraz 555. Always confirm chemical compatibility against your specific fluid before substitution.
How much does Simriz SZ481 cost?
FFKM O-rings such as Simriz SZ481 are typically £30 to £500 per piece depending on size, with custom or large-bore parts at the upper end. Get a current quote via the form on this page.
Where can I buy Simriz SZ481 in the UK?
Simriz SZ481 is supplied in the UK by independent FFKM seal specialists with multi-brand inventory. Lead time is 2-5 working days for stock BS/AS568 sizes, 4-8 weeks for custom-moulded sizes.
References
- Freudenberg-NOK — Manufacturer
- ISO 3601 O-ring sizes
- BS 1806