O-rings
Highest quality O-rings
60 years of expertise in O-rings
We have been producing O-rings for over 60 years at our facility in Ammersbek and at our subsidiary in Italy. Our focus lies on high-performance materials such as FKM and FFKM, with FFKM resistant to temperatures of up to 320 °C.
The main advantages of O-rings lie in their simple geometry, their reliable function as sealing elements, and their excellent price-performance ratio.
Our innovation-driven laboratory develops application-oriented compounds, enabling customized solutions tailored to your specific requirements.
The result: maximum media and temperature resistance.
- O-rings according to DIN ISO 3601-1 (replaces 3771), grade characteristic N+S
- Inner diameter of 0.5 – 2000 mm
- Standard and individual special compounds
- O-ring boxes for sorted applications
- Cord rings according to DIN ISO 3302-1, KI.E2
FFKM heat-resistant
Inner diameter
Compression molding
Tools
O-Ring Tolerance Calculator
Based on DIN ISO 3601-1 – for inner diameter (d1) and cross-section (d2)
Tools
Thanks to our own toolmaking, we have the possibility of cost-effective and fast production of your O-ring dimension with special tolerances from the desired or required material.
Storage
For the storage of O-rings, DIN 7716 (guidelines for storage, maintenance and cleaning of rubber products) basically applies. Proper storage is important. The service life of O-rings can be influenced and thus changed by many factors, such as light, heat, humidity, oxygen, ozone, etc. The ideal temperature for storage is between +5 to +20 °C. In general, storage sealed in polyethylene bags is considered optimal. We recommend not significantly exceeding the following storage times:
Comparison Table
| Material | ✔ | ✘ |
|---|---|---|
| ACM | Mineral oils (engine, transmission and ATF oils), aging and ozone | Aromatic and chlorinated hydrocarbons, brake fluids, hot water, steam, acids and alkalis |
| CR | Water, aqueous solutions at low temperatures, refrigerants, aging and ozone | Aromatic hydrocarbons, esters, ketones and glycols |
| EPDM | Brake fluids, various acids and alkalis, hot water and steam, aging and ozone | Mineral oils and greases, natural gas, linoleic acid, ethers, hexane, gas oil, Freon 112 |
| FFKM | Extremely high temperatures (air up to 270 °C – special compounds up to 315 °C), resistant to solvents and over 1600 media | Liquid oxygen, dichloroacetic acid |
| FKM | High temperatures up to 200 °C (medium air), mineral oils, vegetable and animal fats, aromatic and chlorinated hydrocarbons, aging and ozone | Brake fluids, highly polar solvents, acetone, caustic potash, formic acid, acetic acid, chlorobenzene |
| HNBR | Vegetable and animal fats and oils, aliphatic hydrocarbons, water and steam up to 140 °C, aging and ozone | Chlorinated hydrocarbons, solvents, concentrated acids/alkalis |
| NBR | Gasoline, mineral oils and greases, light fuel oil, propane, butane, aliphatic hydrocarbons | Premium fuels with high aromatic content, benzene, acetone, brake fluid, ozone |
| PTFE | Almost all organic and inorganic chemicals (over 1800 media), high and low temperature applications, weathering and aging | Alkali metals in molten or dissolved form, fluorine and fluorine compounds |
| VMQ | High temperatures, hot air, oxygen, water, aging and ozone | Silicone oils and greases, fuels, exhaust gases |
Can consist of the following materials.
| MATERIAL ISO 1629 | BASE ELASTOMER | TRADE NAME / BRAND | TEMPERATURE RANGE (STANDARD) |
|---|---|---|---|
| ACM | Polyacrylate rubber | Nipol® | -20° to +150°C |
| AEM | Ethylene acrylate rubber | Vamac® | -30° to +150°C |
| AU | Polyester urethane | Adipren® | -30° to +90°C |
| CR | Chloroprene rubber | Neoprene® | -40° to +100°C |
| CSM | Chlorosulphonyl polyethylene rubber | Hypalon® | -30° to +120°C |
| EPDM | Ethylene propylene diene rubber | — | -40° to +150°C |
| FEPM | Tetrafluoroethylene propylene copolymer rubber | Aflas® | -30° to +200°C |
| FFKM | Perfluoro rubber | HPF | -15° to +270°C |
| FKM | Fluoro rubber | Viton® | -20° to +200°C |
| FVMQ | Fluorosilicone rubber | Silastic® | -45° to +175°C |
| HNBR | Hydrogenated nitrile butadiene rubber | — | -15° to +150°C |
| IIR | Butyl rubber | Polysar Butyl® | -40° to +130°C |
| NBR | Nitrile butadiene rubber | Perbunan® | -25° to +100°C |
| PTFE | Polytetrafluoroethylene | Teflon® | -200° to +260°C |
| SBR | Styrene butadiene rubber | Intol® | -40° to +100°C |
| VMQ | Methyl vinyl rubber / silicone | Silopren® | -50° to +210°C |
Durability
| MATERIAL | SHELF LIFE |
|---|---|
| NBR | 4 years |
| HNBR | 4 years |
| FKM/FPM | 10 years |
| VMQ | 10 years |
| EPDM | 6 years |
| CR | 4 years |
Frequently Asked Questions about O-Rings
What materials are available for O-rings and when is each used?
O-rings are manufactured from different elastomers depending on the application. NBR (nitrile rubber) is particularly common and is suitable for oils, greases and hydraulic applications. FKM (Viton®) is used when high temperatures or aggressive chemicals are involved. For especially demanding applications, FFKM (perfluoroelastomer) is used. This high-performance material offers extremely high chemical resistance as well as temperature resistance exceeding +300 °C and is frequently used in the chemical, pharmaceutical or semiconductor industries. EPDM is resistant to water, steam and many cleaning agents, while silicone (VMQ) stands out due to its wide temperature range and flexibility.
The correct material selection depends on the medium, temperature, pressure and environmental conditions. An incorrect material choice can lead to premature wear, swelling or leakage.
How do I find the correct size for an O-ring?
The correct O-ring size is defined by two dimensions: inside diameter and cross-section (cord thickness). To determine the size, either measure the existing O-ring with a caliper or measure the groove in which it is installed. It is important that the O-ring is slightly compressed in the installed condition to ensure reliable sealing. Many O-rings are standardized according to DIN or ISO standards, making it easier to find suitable replacement parts. In addition to diameter, tolerances and installation space also play a role. In dynamic applications (e.g. moving pistons), additional factors such as friction and pressure must be considered.
How long do O-rings last and what influences their service life?
The service life of an O-ring depends on several factors: material quality, temperature, pressure load, chemical influences and correct installation. High temperatures accelerate the aging of the elastomer, while improper lubrication or mechanical overextension can lead to cracks. UV radiation or ozone can also attack certain materials. In static applications, O-rings often last many years, whereas in dynamic movements they are exposed to greater wear. Proper material selection, correct dimensioning and regular maintenance significantly increase service life and reduce the risk of leakage or machine failure.
Up to what pressure can O-rings be used?
The pressure resistance of O-rings depends on the material, installation situation and extrusion gap. In static applications, O-rings can often seal pressures of several hundred bar. At higher pressures, however, there is a risk of so-called extrusion, where the elastomer is pressed into the sealing gap. In such cases, back-up rings are used to stabilize the O-ring. Harder materials or higher Shore hardness also improve pressure resistance. For high-pressure applications, precise design of the groove, extrusion gap and material is crucial to ensure safe and durable sealing.
According to which standards are Höfert O-rings manufactured?
The O-rings at Höfert are manufactured in accordance with DIN ISO 3601-1 (which replaced the former DIN 3771), ensuring a high level of interchangeability and consistent quality. In addition, Höfert also offers individual special compounds and special tolerances, which can be custom-manufactured in the company’s in-house toolmaking department.