The quality of the sealing surface directly affects the service life of the valve, and the material of the sealing surface is an important factor in ensuring the quality of the sealing surface. Therefore, the following factors should be considered when selecting the valve sealing surface material:
Corrosion resistance
"Corrosion" refers to the process in which the sealing surface is damaged by the medium. If the surface is damaged in this way, the sealing performance cannot be guaranteed. Therefore, the sealing surface material must be corrosion-resistant.
Friction resistance
"Friction" refers to the damage caused by friction during the relative movement of the sealing surface. This damage will inevitably cause damage to the sealing surface, and the friction resistance of the material is often determined by the internal properties of the material.
Erosion resistance
"Erosion" refers to the process in which the sealing surface is damaged when the medium flows through the sealing surface at high speed. This damage is more obvious in throttle valves and safety valves used in high-temperature and high-pressure steam media, and has a great impact on the damage to the sealing performance.
It should have a certain hardness, and the hardness will drop greatly at the specified working temperature.
The linear expansion coefficient of the sealing surface and the body material should be similar, which is more important for the structure with the sealing ring, so as to avoid additional stress and looseness at high temperature.
When used under high temperature conditions, it must have sufficient resistance to oxidation, thermal fatigue, and thermal cycling.
