Rubber O-rings are very common spare parts for sealing materials. Understanding the materials and application scope of common O-rings can help eliminate shortages and purchase spare parts for daily maintenance on site.
Common O-ring materials in thermal power plants are: nitrile (NBR), ethylene propylene diene monomer (EPDM), natural rubber (NR), neoprene (CR), polyurethane rubber (PU, AU, EU), silicone rubber (Si ), fluoro rubber (FPM), hydrogenated nitrile rubber (HNBR), perfluoro rubber (FFKM) are often seen on the label of the O-ring, the English expression of the size and the material of the O-ring.
Use temperature of natural rubber: -60℃～+80℃,
Excellent mechanical properties, elasticity, and processability.
It is easy to age and deteriorates; it is not resistant to oil and heat.
Nitrile-butadiene (NBR) operating temperature: -30℃～+110℃, resistant to gasoline and aliphatic hydrocarbon oils, second only to polysulfide rubber and fluoro rubber, with good heat resistance, wear resistance, and water resistance.
Not resistant to cold, acid, poor electrical insulation, and not resistant to polar solvents.
EPDM (EPDM operating temperature: -40 ℃ ~ +150 ℃, good aging resistance, ozone resistance, UV resistance, weather resistance. Excellent electrical insulation, chemical resistance, good impact elasticity, acid, and alkali resistance. Super Resistant to water, superheated water and water vapor. Resistant to polar solvents such as ketones, esters, etc., and has good elasticity and compression deformation resistance.
Not resistant to aliphatic and aromatic hydrocarbons, not easy to bond, slow vulcanization, and not resistant to oil.
Polyurethane rubber (PU, AU, EU) operating temperature: -30℃～+80℃, quite wear-resistant, high tensile strength, high elongation; high hardness, good elasticity, good oil resistance; aging resistance, good air tightness.
Poor temperature resistance, poor water, and alkali resistance, and poor resistance to aromatic hydrocarbons, chlorinated hydrocarbons, ketones, esters, alcohols, and other solvents.
Silicone rubber (Si) operating temperature: -60°C to +210°C, high-temperature resistance (up to 300°C) and low-temperature resistance (minimum -100°C), excellent electrical insulation, high stability, and high chemical inertness. With a hydrophobic surface and physiological inertness, it is harmless to the human body. High breathability.
Poor mechanical strength, poor oil resistance, solvent resistance, and acid and alkali resistance, more difficult to vulcanize, and more expensive.
Fluorine rubber (FPM) operating temperature: -20℃～+200℃, high-temperature resistance (long-term use below 200℃, short-term can withstand high temperature above 300℃); acid and alkali resistance, oil resistance, radiation resistance, high vacuum resistance performance; Excellent electrical insulation, mechanical properties, chemical resistance, ozone resistance, and atmospheric aging resistance. It has non-extinguishing properties and is a self-extinguishing rubber.
However, it has poor processability, poor cold resistance, low elasticity, and breathability, and is expensive.
Hydrogenated nitrile rubber (HNBR) operating temperature: -20℃～+150℃, the temperature resistance and weather resistance are much better than general nitrile rubber, oil resistance is close to nitrile rubber; high mechanical strength and wear resistance, mainly used for Oil and high-temperature resistant sealing products.
Perfluororubber (FFKM) operating temperature: -25℃~+260℃, excellent high-temperature hardening resistance, good elasticity, excellent chemical resistance, acid, alkali, ketone, ester, ether, strong oxidant and other chemicals Corrosion of more than 1600 kinds of chemicals, the highest heat resistance can reach 320 ℃, and it is generally used to solve the ultimate sealing problem. Just too expensive, quite expensive.
To learn more, please refer to: Custom Special Rubber Seals Company