How to choose pneumatic valve sealing surface material

and corrosion. 'Corrosion' namely sealing surface under the effect of medium, the damage to the surface of the process. If all this damage the surface, sealing cannot guarantee, therefore, sealing materials must be resistant to corrosion. The corrosion resistance of materials mainly depends on the material and its chemical stability.
and abrasion resistance. 'Scrape' the sealing surface of relative movement process, the damage to materials caused by friction. The damage will cause the destruction of the sealing surface, therefore, the sealing surface material must have good abrasion resistance, the standard it is pneumatic valve gate. The scratch resistance of materials is often determined by the internal material properties.
and erosion resistance. 'Erosion' that is medium to high speed through the sealing surface, ruined the sealing surface of the process. The damage in high temperature and high pressure steam medium throttling pneumatic valve, safety valve used is more apparent, had a great influence on sealing failure, therefore, resistance to erosion and it is one of the important requirement of sealing surface material.
and should have a certain hardness and under specified operating temperature hardness under the big decline.
and sealing surface and bulk materials should approximate linear expansion coefficient, the setting and the structure of the sealing ring is more important, in order to avoid high temperature easy to generate additional stress and cause is loose.
, used in high temperature conditions, to have enough resistance to oxidation and thermal fatigue resistance and thermal cycle.
in the current situation, to find a comprehensive meet above requirement is hard to do the sealing surface of materials, only depending on the pneumatic valve and purpose, focus on satisfy certain requirements. For example, in the medium used in pneumatic valves should pay special attention to the sealing surface erosion resistant requirements; They should choose to medium containing solid impurities in high sealing surface hardness materials.