What Material Is Commonly Used for Hydraulic Seals?

Hydraulic seals play a crucial role in preventing fluid leakage and maintaining the efficiency of hydraulic systems. The choice of material for these seals is essential, as it directly impacts their performance and longevity. Here are some of the most commonly used materials for hydraulic seals and their advantages：
 
Commonly Used Materials
1. Nitrile Rubber (NBR)
Nitrile rubber is widely used due to its excellent oil resistance and wear resistance. It performs well in medium pressure and temperature hydraulic systems, maintaining stable performance between -40°C and 100°C. This makes it an ideal choice for both static and dynamic sealing applications. However, its high-temperature resistance is relatively weak, making it unsuitable for extreme high-temperature environments.
 
2. Hydrogenated Nitrile Rubber (HNBR)
Hydrogenated nitrile rubber is an improved version of NBR, offering enhanced heat and chemical resistance. It can maintain good sealing performance at higher temperatures (up to 150°C) and is suitable for high-temperature, high-pressure hydraulic systems. This material is particularly effective in environments with corrosive media.
 
3. Polyurethane (PU)
Polyurethane seals are known for their high strength, excellent wear resistance, and good oil resistance. They perform well in extreme working conditions and are commonly used in heavy-duty equipment such as construction machinery and metallurgical devices. However, PU has relatively weak low-temperature performance, which may require optimization based on specific working conditions.
 
4. Polytetrafluoroethylene (PTFE)
PTFE is a high-performance synthetic material with exceptional chemical resistance and a low friction coefficient. It maintains stable performance across an extremely wide temperature range (-200°C to 260°C) and is ideal for high-temperature, high-pressure, and high-precision hydraulic systems. PTFE is often used in industries such as food and pharmaceuticals where hygiene and chemical resistance are critical. However, its wear resistance is relatively weak, so it is often used in combination with other materials.
 
5. Fluororubber (FKM)
Fluororubber boasts outstanding high-temperature performance and chemical resistance, maintaining stability at temperatures exceeding 200°C. It is compatible with various hydraulic media, including mineral oils and synthetic oils, making it suitable for extreme working conditions. However, FKM is more expensive, and its elasticity at low temperatures may be affected.
 
6. Composite Materials
Composite seals, made from combinations of materials such as rubber and plastic or metal and rubber, can better adapt to complex working conditions. For example, a composite of polyurethane and rubber can combine the strengths of both materials, offering higher wear resistance and elasticity. These materials are particularly suitable for extreme conditions such as high pressure, high speed, and high temperature, making them ideal for high-end hydraulic systems.
 
Advantages of These Materials

• NBR: Economical, widely used, good oil and fuel resistance, suitable for medium temperature range (-30°C to 120°C).
• HNBR: Enhanced heat and chemical resistance compared to NBR, suitable for higher temperatures and corrosive environments.
• PU: High strength, excellent wear resistance, good oil resistance, suitable for extreme working conditions.
• PTFE: Exceptional chemical resistance, low friction coefficient, wide temperature range, suitable for high-precision applications.
• FKM: Outstanding high-temperature performance, good chemical resistance, suitable for extreme conditions.
• Composite Materials: Combine the advantages of different materials, offering higher wear resistance and elasticity, suitable for complex and extreme working conditions.