The O-ring material is an important factor when choosing the right component for your application. Industrial O-rings are commonly manufactured in 15 or so different materials. As each material has different characteristics, including varying temperature resistances, then each is better suited to a particular industry or purpose.
The following is an overview of the main types of O-ring material for use as a guide when selecting the right component. For free advice on choosing suitable O-rings for your industry, please don’t hesitate to give one of our technical sales team a call.
Commercial Quality O-Rings
Most O-rings used for industrial fluid power systems fall under the Grade N standard of ISO 3601-3. The O-rings we supply in this category are quality products that give a good service life and a high level of performance. Commercial, or ‘standard’ O-ring materials can be found in both static and dynamic systems, with a range of pressure and temperature scales.
The most common O-rings in this category are:
Nitrile (Acrylonitrile Butadliene)
Nitrile content in an O-ring conveys a high level of hydrocarbon resistance, so this is a popular choice for systems that utilise mineral oils. Nitrile is also suitable for use where water and solvents are present. Nitrile O-rings are tough components, resistant to abrasion and with a temperature range of - 40°C to 110°C with excursion to + 135°C. Nitrile O-rings are further categorised according to their nitrile content, with different properties for low, medium and high nitrile O-rings.
Ethylene – Propylene
Ethylene O-rings can be used in water based systems, where their high resistance to hot steam (up to 125°C) conveys an advantage over other materials. Ethylene is also naturally resistant to ethanol, glycol, acids and alkalis.
Silicone & Fluorosilicone
Silicone O-rings are general-purpose components with a good level of resistance to electricity and weathering. However, they can tear easily and are not the best choice for applications where high tensile strength is needed.
Other Standard Materials
O-rings can also be sourced in neoprene, natural rubber, butyl, epichlorhydrin, polyurethane, and chlorosulphonyl-polyethylene.
O-rings can be sourced in high-performance materials where an extremely high tensile strength, abrasion resistance or wide temperature range is needed. Under the ISO 3601 standards, these are covered under Grade S; for some aerospace and automotive manufacturing applications, and Grade CS (Criticial Service) for some medical applications and aeroplane parts.
There are several commonly used high-performance materials, of which the most common is:
Fluoroelastomer O-rings are commonly branded as Viton. Viton has a temperature resistance of up to 200°C, making it a good choice for oil based hydraulic systems, including those using petrol. Fluorocarbons also have a natural resistance to ozone and weathering, making them durable components in dynamic, mechanical applications. Viton O-rings should not be used with ketone or heated acids.
Other High-Performance Materials
Whatever your industrial application, you are certain to find a specialist O-ring to suit your needs. Some materials are known for their high abrasion resistance, others for being extremely inert when exposed to alkalis or acids. High performance O-rings are available made of polytetrafluoroethylene, kalrez, and hydrogenated nitrile.
Choosing The Right Material For Your O-Ring Application
More information about O-ring materials can be found on the compound information page on our website. Here you can download our full technical catalogue giving details of all the O-ring materials we stock. You can also find out more about the use of different O-ring materials in our free O-Ring Guide. Our new e-book helps you find O-rings by material, size and performance characteristics. Click here to download your copy.