Needle valve material selection

Under normal circumstances, needle valve materials shall be in accordance with its parameters and properties of the materials selected in accordance with this standard and shall comply with the relevant product standard requirements. Can also use the performance of not less than specified in this standard or for a contract the two sides agreed to purchase other materials.

The exceptional circumstances, the technical requirements of needle valve are as follows:

1. Gray cast iron needle valve

For the nominal pressure pN ≤ 1.0MPa, a temperature of -10 ~ 200 ℃ of water, steam, air, gas and oil and other media, gray cast-iron valves, the main part materials selected according to Table 1.



2. Malleable iron needle valve

For the nominal pressure pN ≤ 2.5MPa, a temperature of -30 ~ 300 ℃ of water, steam, air and oil and other media malleable iron valves, the main part materials selected according to Table 2.



3. Ductile iron needle valve

For the nominal pressure pN ≤ 4.0MPa, a temperature of -30 ~ 350 ℃ of water, steam, air and oil and other media, ductile iron system of valves, the main part materials selected according to Table 3.



4. Copper alloy needle valve

PN pN ≤ 2.5MPa for water, sea water, oxygen, air, oils and other media, as well as the temperature of -40 ~ 250 ℃ steam medium copper alloy valves, the main part materials selected according to Table 4.



5. Carbon steel needle valve

For the nominal pressure pN ≤ 32.0MPa, a temperature of -30 ~ 450 ℃ of water, steam, air, hydrogen, ammonia, nitrogen and petroleum products such as medium carbon steel valves, the main part materials selected according to Table 5.



6. High temperature steel needle valve

For the nominal pressure pN ≤ 16.0MPa, the temperature is less than or equal to 550 ℃ steam and petroleum products such as media, high-temperature steel valves, the main part materials selected according to Table 6.



7. Cryogenic steel needle valve

For the nominal pressure pN ≤ 6.4MPa, the temperature is higher than or equal to -196 ℃ ethylene, propylene, liquefied natural gas and liquid nitrogen cryogenic medium such as steel valves, the main part materials selected according to Table 7.



8. Stainless acid-proof steel needle valve

For the nominal pressure pN ≤ 6.4MPa, temperature is less than or equal to 200 ℃ of nitric acid, acetic acid and other media, stainless steel valves, the main part materials selected according to Table 8. 

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