The sealing surface is a critical part of any type of valve. The same applies to carbon steel gate valves, so it is important to choose the right material for the sealing surface. The material of the sealing surface must meet at least the following criteria.
1, corrosion resistance.
If the sealing surface is poor in corrosion resistance, it is easily corroded by the medium and the sealing performance will naturally become poor. Therefore, the sealing surface material must be resistant to corrosion. Corrosion resistance of materials is mainly determined by the materials and their chemical stability.
It is easy to scratch the sealing surface during the movement of the medium. The scratch resistance of the sealing surface material must be very good, especially the gate valve. The scratch resistance of materials is mostly determined by the internal properties of the material.
3, erosion resistance.
"Erosion" is the process in which the sealing surface is destroyed when the medium flows through the sealing surface at high speed. The throttle valve and safety valve used in such high-temperature and high-pressure steam media destruction are more obvious and have a great impact on the sealing performance.
4, good hardness.
And at the specified operating temperature, a large drop occurs in hardness.
5, expansion coefficient.
The linear expansion coefficient of the sealing surface and the body material should be similar, which is more important for the structure of the sealing ring, so as to avoid excessive stress and looseness at high temperatures.