Selection materials for valve sealing surface
The valve sealing surface is generally selected according to:
1. Operating temperature of the valve.
2. Working pressure and corrosiveness of the medium.
3. The type of valve and the structure of the sealing surface.
4. The sealing specific pressure and the allowable specific pressure.
5. The manufacturing conditions and equipment processing capacity of the enterprise.
6. Surfacing technology capabilities.
7. User's requirements.
The optimized design should also be adopted to select the sealing surface material with low price, simple production process and high production efficiency under the condition of satisfying the service performance of the valve.
The sealing surface is the key part of the valve, and its quality directly affects the service life of the valve. Reasonable selection of the material of the valve sealing surface is one of the important ways to improve the service life of the valve. We need to avoid misunderstanding when selecting the sealing material of the valve.
Myth 1: The hardness of the valve sealing surface material is high and its wear resistance is good.
Experiments have shown that the wear resistance of the valve sealing surface material is determined by the structure of the metal material. Some metal materials with austenite as the matrix and a small amount of hard material are not very hard, but their wear resistance is very good. The valve sealing surface has a certain high hardness to avoid being scratched by hard objects in the medium. Considering the hardness value, HRC35-45 is suitable.
Myth 2: The price of the valve sealing surface material is high and its performance is good.
The price of a material is its own commodity characteristics, and the performance of the material is its physical property, there is not necessary connection between them. The cobalt in the cobalt-based alloy is imported and the price is higher, so the price of the cobalt-based alloy material is high. Cobalt-based alloys are characterized by high temperature wear resistance. But at normal temperature and medium temperature conditions, the material with lower price/performance should be selected, and not necessary to select cobalt-based alloy material.
