Selection of material
Normally, needle valve materials should be based on the parameters and the properties of materials according to the standard, and shall conform to the relevant provisions of the standard products. Also can choose performance not less than the standard for the purchase contract or agreed by the parties and other materials.
And special circumstances needle valve technical requirements are as follows:
1 needle valve of grey cast iron
For nominal pressure, temperature than 1.0 MPa pN -- 10 ~ 200 ° c for the water, steam, air, gas and oil of grey system, etc.
2 malleable iron needle valve
For nominal pressure, temperature than 2.5 MPa pN for - 30 ~ 300 degrees of water, steam, air, and oil, and other media malleable iron valves.
3 ductile cast iron needle valve
For nominal pressure, temperature pN than 4.0 MPa -- 30-35 ° c for the water, steam, air and oil of nodular cast iron, etc.
4 copper gold needle valve
For more than 2.5 MPa pN nominal pressure of oxygen in water, water, air, oil, such as temperature, medium for - 40 ~ 250 ° steam medium copper gold valve.
5. Carbon steel needle valve
For nominal pressure, temperature 32.0 MPa pN acuities -- 30-45 ° c for the water, steam, air, hydrogen, ammonia nitrogen and petroleum products, medium carbon steel valves.
6 the steel needle valve type high temperature
For nominal pressure, temperature 16.0 MPa pN acuities were less than or equal to 55 degrees of steam and petroleum products, etc. High steel valves
7. Cryogenic steel needle valve
For nominal pressure, temperature pN acuities 6.4 MPa is greater than or equal to - 196 degrees of ethylene, propylene, liquid, gas and liquid medium low-temperature steel valves, etc.
8. Stainless steel needle valve acid-proof
For nominal pressure, temperature pN acuities 6.4 MPa than or equal to 200 degrees of nitric acid, acetic acid, etc stainless steel valves.
