Valve sealing surface is the most important face, the sealing surface quality directly affects the life of the valve sealing surface of the material surface is to ensure that an important factor in the quality of the sealing surface. Therefore, the choice should be considered when the valve sealing surface of the material the following factors:

      ¢Ù corrosion. "corrosive" effect of the sealing surface in the media, the surface damage process. If the surface is affected by such damage, sealing can not be guaranteed, therefore, the sealing surface material must be resistant to corrosion. Corrosion resistance of materials depends on the material and its extreme chemical stability.

      ¢Ú Scratch. "scratch"that the sealing surface during relative movement of material damage caused by friction. The damage would inevitably lead to the destruction of the sealing surface, therefore, the sealing surface material must have good anti-abrasion properties, in particular valve. Scratch resistance of materials is often determined by the material of an internal nature.

      ¢Û resistant to erosion. "erosion"that flows through the sealing surface when high-speed media, so that the process of the destruction of the sealing surface. The damage at high temperature, high pressure steam used in the media throttle valve more obvious destruction of a great impact on the seal, therefore, resistant to erosion is also an important requirement for the sealing surface of the material.

      ¢Ü should have a certain hardness, and in the work place under a large temperature decrease in hardness.

      ¢Ý sealing surface and the bulk material should be approximately linear expansion coefficient, which is more important to set the structure of ring in order to avoid high temperature stress and prone to cause additional loose.

      ¢Þ use in high temperature conditions, have enough anti-oxidation, thermal fatigue and thermal cycling and other issues.

      In the present circumstances, to find full compliance with the requirements of the sealing surface material is very difficult to do, only depending on the valve and use, focusing on meeting certain requirements. For example, in valves used in high-speed media, special attention should be sealing surface erosion resistance requirements; the medium containing the solid impurities should be chosen when the sealing surface of high hardness materials.