AS568-395 FFKM O-Ring — 658.88 × 5.33 mm
A thick, durable section engineered for large-diameter static seals and high-tolerance groove applications. With an inside diameter of 658.88 mm and a 5.33 mm cross section, this is a very-large seal for the largest diameters and heavy static service. Moulded from Aperflu 2275 perfluoroelastomer (FFKM) for continuous service up to 200 °C, this seal resists hot acids, caustics, solvents, fuels and steam.
Dimensions
| Dash number | AS568-395 |
|---|---|
| Inside diameter (ID) | 658.88 mm (25.94 in) |
| Cross section (CS) | 5.33 mm (0.21 in) |
| Outside diameter (OD) | 669.54 mm (26.36 in) |
| Material | Aperflu 2275 perfluoroelastomer (FFKM) |
| Service temperature | up to 200 °C continuous |
Oil refining
Distillation units, catalytic crackers and hydrotreaters expose seals to hot hydrocarbons, sour streams and steam. Aperflu 2275 maintains a stable seal through thermal cycling and aggressive process media.
Why Aperflu 2275 FFKM
Compared with bisphenol-cured FKM, peroxide-cured FFKM keeps its sealing force longer at temperature — critical for static and slow-dynamic duty in chemical service.
Typical applications
Large flanges, vessel and tank closures, heavy machinery and static joints, where Aperflu 2275 outperforms FKM and EPDM in aggressive media and elevated temperature.
Compound properties
| Property | Typical value | Test method |
|---|---|---|
| Hardness | 70 – 71 Shore A | GB/T 39693.4 |
| Tensile strength | 21.2 – 21.8 MPa | GB/T 528 (dumbbell type 2) |
| Elongation at break | 155 – 170 % | GB/T 528 (dumbbell type 2) |
| Compression set, 200 °C × 70 h (25 %, method B) | 15 – 16 % | GB/T 7759.1 |
All values are typical. Every batch is shipped with an individual certificate of analysis and may differ from the typical values listed here.
Chemical resistance
| Media group | Rating |
|---|---|
| Hot organic & inorganic acids | Excellent |
| Caustics (NaOH up to 50 %) | Excellent |
| Ketones, aldehydes, esters, ethers, alcohols | Excellent |
| Solvents, fuels, hydrocarbons, sour gases | Excellent |
| Steam and hot water | Excellent |
| Amines (high temperature, concentrated) | Good – contact us for grade selection |
| Clean-in-place (CIP) / steam-in-place (SIP) agents | Excellent |
| Active pharmaceutical ingredients (APIs) | Excellent |
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