Body, bonnet and gate (valve) is one of the main parts of the valve, direct exposure to media pressure, the materials used must comply with the "valve pressure and temperature rating" requirement. Commonly used materials are the following categories:

1.Grey cast iron: Cast iron for nominal pressure PN ≤ 1.0MPa, temperature -10 ℃ ~ 200 ℃ of water, steam, air, gas and oil and other media. Common grades of gray cast iron: HT200, HT250, HT300, HT350.

2.Malleable iron: for nominal pressure PN ≤ 2.5MPa, temperature is -30 ~ 300 ℃ of water, steam, air and oil medium, commonly used grades are: KTH300-06, KTH330-08, KTH350-10.

3.Ductile iron: for PN ≤ 4.0MPa, temperature of -30 ~ 350 ℃ of water, steam, air and oil and other media. Common brands are: QT400-15, QT450-10, QT500-7. Given the current level of domestic technology, the plant is uneven, the user is often difficult to test. According to experience, the proposed PN ≤ 2.5MPa, valves or the use of steel as a safety valve.

4.Acid and high silicon iron: for nominal pressure PN ≤ 0.25MPa, temperature below 120 ℃ corrosive media.

5.Carbon steel: suitable for nominal pressure PN ≤ 32.0MPa, temperature of -30 ~ 425 ℃ of water, steam, air, hydrogen, ammonia, nitrogen and petroleum products and other media. Common brands are WC1, WCB, ZG25 20,25,30 and high quality steel and low alloy steel 16Mn.

6.Copper alloys: for PN ≤ 2.5MPa water, sea water, oxygen, air, oil and other media, as well as temperature -40 ~ 250 ℃ steam medium, commonly used grades for ZGnSn10Zn2 (bronze), H62, Hpb59-1 (yellow copper), QAZ19-2, QA19-4 (aluminum bronze).

7.High copper: for nominal pressure PN ≤ 17.0MPA, temperature ≤ 570 ℃ steam and petroleum products. Common brands are ZGCr5Mo, 1Cr5M0. ZG20CrMoV, ZG15Gr1Mo1V, 12CrMoV, WC6, WC9 other brands. The specific choice of the valve must be in accordance with the pressure and temperature specification.

8.Low temperature steel, suitable for nominal pressure PN ≤ 6.4Mpa, temperature ≥ -196 ℃ ethylene, propylene, liquefied natural gas, liquid nitrogen and other media, commonly used grades) have ZG1Cr18Ni9, 0Cr18Ni9, 1Cr18Ni9Ti, ZG0Cr18Ni9.

9.Acid-resistant stainless steel, suitable for nominal pressure PN ≤ 6.4Mpa, temperature ≤ 200 ℃ nitric acid, acetic acid and other media, commonly used grades are ZG0Cr18Ni9Ti, ZG0Cr18Ni10 , ZG0Cr18Ni12Mo2Ti, ZG1Cr18Ni12Mo2Ti .

  Keywords:butterfly valve ,knife gate valve,ball valve,globe valve,slurry gate valve