Chemical resistance characteristics of O-rings and selection recommendations
Chemical resistance is a key consideration when selecting an O-ring. Different materials, such as perfluoroelastomer (FFKM), fluoroelastomer (FKM) and nitrile rubber (NBR), vary in their resistance to chemicals. How to choose the right material according to the type of medium, temperature and pressure in the working environment? At the same time, factors such as the size, tolerance and hardness of the O-ring need to be considered to ensure its sealing effect.
Chemical resistance
The resistance of O-rings to chemicals is one of the most important properties in a variety of industrial applications. Among them, perfluoroelastomer (FFKM) is a high-performance material with particularly outstanding chemical resistance. According to authoritative test data, FFKM can withstand more than 1,600 chemicals, including strong acids, strong alkalis, organic solvents, etc. Even in extreme chemical environments, FFKM retains its excellent elasticity and sealing properties.
In addition, FFKM has excellent heat resistance. According to the experimental data, FFKM can maintain good sealing performance in the continuous operating temperature range (-39°C to 288°C). Even in high-temperature environments (e.g. constant temperature of 316°C or intermittent high temperature of 343°C), FFKM does not exhibit significant hard bottoming and aging.
Selection suggestions
Material selection: Select the right material according to the application environment. For applications that require chemical resistance, FFKM is the first choice. For general applications, fluoroelastomers (FKM) and nitrile rubber (NBR) are also good choices.
Size & Tolerance: Choose the appropriate O-ring according to the size and tolerance of the sealing groove. Ensure the accuracy of the fit of the O-ring to the sealing groove to avoid leakage problems caused by size mismatch.
Hardness selection: Select the appropriate hardness according to the actual application scenario. In general, the stiffer O-rings are suitable for high-pressure and high-speed motion applications, while the softer O-rings are suitable for low-pressure and low-speed motion applications.
