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FKM & Viton: Can it be used in steam applications?

O rings.
Image Source: Wikipedia

Fluoroelastomers have many uses in various applications and configurations, such as O-rings, U-cups, Lip Seals and gaskets. There are many misconceptions surrounding FKM and Viton™. Many people are under the impression that there is only one type of polymer. Some believe that FKM can withstand temperatures down to -60°C. But the most common misconception by far is that there is a difference between FKM and Viton™. This can lead to misunderstandings when setting up specifications on the right polymer for the application.

First of all, what is FKM?

FKM is the ASTM International (formerly American Society for Testing and Materials) designation for the fluoroelastomer category. It is not a mark of quality. Not all FKM O-rings are equivalent, and some may fall short on desired performance. Especially if they are not properly specified for applications such as steam systems.

Fluoroelastomer is a highly resilient type of synthetic rubber and its hard-wearing qualities make it a popular choice in the oil and gas industries. The material is widely used when dealing with aggressive fuels and chemicals that would rapidly degrade other rubbers.

However, despite the material’s undeniable usefulness, there is a lot of confusion as to what its proper name is. This can lead to problems when ordering the correct material. Especially when customers request for Viton™ over FKM, which is like a customer asking for a Toyota over a car.

Then what is Viton™? How is it similar/different to FKM?

Fluoroelastomer is often referred to as FKM or as Viton. However, Viton™ is a brand of FKM . The Viton™ name is a registered trademark of The Chemours Company (a spin-off company of DuPont). You may see this rubber listed in different places with these two names, but they are all one and the same. At IBEX Australia, we also use Viton as a generic name for the convenience of the customer.

Viton™ was introduced in 1957 and has done an excellent job marketing their FKM, as the market have been using Viton™ as a generic name for FKM (think Jet Ski, which is actually a brand name for a personal water craft). However, Chemours is not the only company that manufactures FKM products.

There are many different FKM players on the market, varying in different levels of fluorine content, viscosity and curing method. Typically, the higher the fluorine content, the better chemical resistance. However, there are several low-cost fluoroelastomer imposters on the market that may put your operations at risk of seal failure. 

A number of manufacturers of finished goods offer products which are being described as “commercial” or “industrial grades” of fluoroelastomer at reduced prices with no supplier guarantee. Some of these products are blends of FKM with hydrocarbon elastomers, such as ethylene-propylene, chloroprene or acrylic rubbers.

Many hydrocarbon rubbers can be blended to take advantage of specific features inherent in the individual rubbers. Fluoroelastomers in general cannot be blended with hydrocarbon rubber without significantly degrading its quality, particularly its reaction to heat.

Whether it is made by Viton™ or not, the key question is: Can your FKM O-rings withstand steam? 

Make sure it can withstand steam and is backed by a guarantee.

IBEX Australia offers FKM O-rings in our High Temperature and Silicone Free range to handle temperatures from -20°C to 200°C, and is one of the only press fit systems in the Australian market that comes with an FKM O-ring that can withstand steam*.

*Technical team must be consulted before installation for all steam applications.

For more information on our FKM O-ring applications, please call us on 1300 85 45 20 .

The technical recommendations contained in this publication are of a general nature, for education purposes and should not be relied on for specific applications without first seeking professional consultation. Whilst IBEX Australia has taken all reasonable steps to ensure the information contained herein is accurate and useful, IBEX Australia does not warrant the accuracy or completeness of the information and does not accept liability for errors or omissions.

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