Hydraulic seals have high sealing performance, that is, in dynamic and static sealing applications, there is no leakage or minimal leakage, wear, corrosion resistance, and friction under extreme conditions such as no pressure, vibration, bending, and material deformation. The safety of work is determined by the stability of the sealing material characteristics, shape, and position. Hydraulic seals must prevent external dust, moisture, coal powder, etc. from entering, and at the same time, sufficient oil film must be maintained on the piston rod (active column) to ensure the normal operation of the hydraulic cylinder.

Due to damage to the seal or a decrease in its effectiveness, the reliability and lifespan of the seal largely depend on the surface quality (roughness, hardness, etc.) of the sealing element, which is also an important factor in the failure of reciprocating seals. About 80% of hydraulic cylinder seal failures are caused by poor emulsion conditions, mainly particle contamination of the oil. The commonly used medium for hydraulic systems of supports is oil in water emulsion, with water accounting for 85%~98%, low viscosity, poor lubrication, rust prevention, and wear resistance, and particularly sensitive to particle wear.

During the assembly of hydraulic cylinders, coarse and hard particles such as abrasives, molding sand, rust scales, and welding slag that fall from the honing bars inside the cylinder are the most lethal to the sealing system of the hydraulic cylinder. Dust, coal powder, and pollutants introduced during the use of emulsions. Such as wear and tear of parts, rust, and peeling of coatings. When an emulsion contaminated with particles flows through a narrow gap at high speed, the particles strike the surfaces of sealing, supporting, and other components at high speed, causing corrosion and wear. The main result of corrosion and wear is erosion pitting.

When there is insufficient lubrication between the sealing and mating surfaces, the rough and uneven surface structure due to poor processing will cause particles to cut open the metal surface or chrome plating layer. A large amount of dust, dirt, floating rust, and pollution particles accumulate together, causing the hard mating surface, namely the chrome plating layer on the piston rod (active column), grinding and wear on the inner surface of the cylinder, and even pulling, resulting in increased leakage, insufficient thrust or unstable movement, crawling, decreased speed, sound and vibration failures.