The material of the mechanical seal:
The mechanical seal is composed of several parts. The materials used are selected according to the role played by the parts, the needs of the mechanical seal structure and the conditions of use. The materials used can be roughly divided into four categories: friction pair materials, auxiliary seals Materials, loaded elastic elements and other structural materials.
In a sense, the friction pair of the seal ring is a comprehensive application of the mechanical properties, chemical properties, and friction characteristics of the material, in order to ensure the long service life and good performance of the friction pair.
The sealing performance.
Principles that should be paid attention to when selecting the material of the friction pair of the seal ring:
1. Strong abrasion resistance, the most important indicator is long service life, less wear means long service life.
2. The corrosion resistance is good, and there should be no reaction products that hinder the sliding characteristics of the end face. The result of corrosion and wear will reduce the life. At the same time, corrosion is to increase the gap between the end faces and increase the leakage of the medium.
3. High mechanical strength. In order to avoid strength damage and end face deformation, materials with certain mechanical strength must be selected.
4. Good heat resistance and thermal conductivity. The frictional heat will adversely affect the wear of the friction pair. In order to prevent the thermal stress of the friction pair from being greater than the allowable stress of the material, which is beneficial to the maintenance of the liquid film between the end faces, the end face material must have Good heat resistance and thermal conductivity.
5. The friction system is small and has a certain degree of self-lubrication. The friction coefficient directly affects the size of the friction heat. In many cases, the friction end is not in a fully lubricated state, so these two factors must be taken into account to select the appropriate friction Sub-group pair.
6. Good air-tightness. The sealing material should be tightly organized, without porosity, and impermeability is a good prerequisite for sealing.
7. Easy to shape and process: It is helpful to reduce the cost and ensure the processing accuracy. So far, no material can meet the above requirements at the same time. The material selection should be based on the main factors that affect the sealing performance and a reasonable structural design should be used to make up for the deficiencies of the material itself, so as to meet the sealing requirements as much as possible.