Material Performance Requirements For Hydraulic Seals

The quality of hydraulic sealing technology will affect the working quality and life of hydraulic support. So what performance should hydraulic seal products have?
1. Temperature resistance
The operating temperature of the seal depends on the temperature of the sealing medium and the temperature rise of the seal itself during movement. The temperature directly affects the sealing performance. Too high a temperature will often accelerate the aging of the sealing material, reduce the elasticity, hardness and other properties of the material, the material hardening; Too low a temperature can also lead to accelerated hardening of the material, loss of elastic properties, and reduce the sealing effect of the material. In summary, materials with a certain temperature range should be used.
2, medium resistance
Because the swelling degree of the material in the medium is a key factor in the sealing performance, the first factor to consider when selecting the hydraulic seal material is whether the selected material can be well compatible with the sealing medium; If the sealing material is compatible with the sealing fluid, it will cause the seal to expand or contract, causing failure in the early days of use. The expansion of the seal causes an increase in friction resistance, and at the same time makes the seal roll. Seal shrinkage will cause the reduction of prepressure, eccentricity compensation ability, until the leak.
3, wear resistance
The wear resistance of the material is one of the important performance indexes of dynamic seal. Good wear resistance, long service life. The wear resistance of the material is closely related to the hardness of the material, the higher the hardness of the material, the better the wear resistance and the longer the service life;
4. Tensile strength
Because the tensile strength of general sealing materials will be accompanied by the increase in temperature and a downward trend, so the selection of materials, must consider its actual maximum use temperature and high temperature mechanical strength. If the tensile strength is too low, a certain amount of stress relaxation or even permanent deformation will occur, resulting in seal failure. The tensile strength is too high, and the performance requirements of the material are too harsh. Therefore, the actual selection of materials, should consider the tensile strength of the material;
5, permanent deformation
Because the sealing capacity of the hydraulic seal is provided mainly by relying on its own recoverable compression deformation in the sealing groove. Therefore, the permanent deformation of the selected sealing material should be small, the elasticity should be strong, and the resilience should be high. In addition, the permanent deformation of the material also has a certain relationship with the temperature change, the temperature is too high or too low will increase the permanent deformation;
6. Flexibility
The so-called extrusion seal refers to a sealing method that obtains the sealing ability by relying on the resilience generated by the sealing material under pressure. Because the lip seal may have a certain amount of eccentricity, it is necessary to rely on the elasticity of the material to compensate for the lack of contact stress of the seal. Therefore, the elasticity of the material is crucial to the sealing effect;
7. Hardness
Hardness is an important indicator of sealing materials, mainly according to the roughness of the sealing surface to determine. When the sealing surface is rough, the hardness of the seal is low, so as to ensure a good sealing effect. Where the sealing pressure is relatively high, the hardness of the seal is required to be appropriately increased, which can prevent excessive deformation of the seal and prevent the phenomenon of the seal being squeezed out. In addition, the hardness of the material decreases with the increase of the use temperature, and the hardness is high, and the wear resistance of the material is also strong.