What is the Ideal O-Ring for Low Temperatures?
Apr 26, 2020
It is vital to understand that most elastomers have different formulas that can reduce the working temperature of the compound. In situations where a certain material has been deemed suitable as a result of its chemical compatibility or even its mechanical properties, there could be a version available for low temperatures. Here we give you a range of O-Rings that are ideal for low temperatures.
Why Does an O-Ring Fail at Low Temperatures?
The process of cooling results in rubber losing its elasticity and this is measured as the Compression Set of the elastomer. The compression set is a vital aspect of how an O-ring performs but it is crucial to ensure that a reliable seal is formed. This is defined by the percentage of material that does not return to its original size after it has been compressed.
Low-Temperature Nitrile O-ring
These have a temperature range of -45°C to 120°C.
Nitrile offers a moderate level of resistance against oils, chemicals and greases. However, it is worth noting that at low temperatures Nitrile is prone to shrinking and could lose chemical resistance.
Low-Temperature HNBR O-Ring
These have a temperature range of -45°C to 120°C. Along with this, they also have improved resistance to both chemicals and oils. However, like Nitrile, it can shrink at lower temperatures and lose its resistance to chemicals.
Low-Temperature Silicone O-ring
These come with a range of temperatures. The standard temperature range is -55°C to +200°C. However, the fluorinated temperature range is -60°C to +230°C while the special low temperature compound temperature range is -100°C to +230°C. They come with a high level of resistance to low temperatures although they are prone to wear while they have little chemical compatibility.
Offering a temperature range of -42°C to +220°C, they also come with a high level of chemical resistance although they are considered to be an expensive solution.
FEP/PFA Encapsulated O-rings
These O-rings offer a temperature range of -60°C to +260°C. The elastomer is also suitable for use in a wide range of working conditions.
Astra Seals® have a temperature range of -250°C to +260°C. This offers the best low-temperature compression set. However, they are only recommended for use in axial sealing applications with no stretch.
To find out more at the NES Astra Seal®, visit https://www.nes-ips.com/astra-seals/