Valve body pressure grade, use temperature and corrosion resistance should not be lower than the requirements of the process connection pipeline, and should give priority to the selection of factory training products.
Water vapor or moisture containing more wet gas and flammable and explosive media, it is not appropriate to choose cast iron valve.
When the ambient temperature is lower than -20℃, it is not advisable to choose cast iron valve.
In the rectangular coordinates composed of dielectric temperature and pressure difference which are more serious in cavitation and erosion, the temperature is 300 ℃, and when the pressure difference is outside the area of 1.5mpa two point connection, the throttle sealing surface should be selected with wear-resistant materials, such as cobalt base alloy or surface surfacing Special Lai alloy.
For strong corrosive media, the selection of corrosion-resistant alloys must be based on the type of media, concentration, temperature, pressure, the selection of suitable corrosion-resistant materials.
Valve body and throttle parts are treated separately, the valve body wall throttling speed is small and allow a certain amount of corrosion, its corrosion rate can be around lmm/years, throttle parts by high-speed scour, corrosion will bow [leakage increase, its corrosion rate should be less than 0.1mm/years. When selecting the lining material, the temperature, pressure and concentration of the working medium must satisfy the use range of the material, and consider the physical and mechanical damage to the valve when it is moved.