Common materials for flange ball valve body, bonnet and valve plate (valve)

There are many materials for manufacturing flanged ball valves, including various grades of ferrous and non-ferrous metals and their alloys, and various non-metallic materials.
    The material used to make the flange ball valve parts is selected according to the following factors:
    1. Pressure, temperature and characteristics of the working medium.
    2. The force of the part and its function in the valve structure.
    3, has a good process.
    4. Under the above conditions, there must be lower costs.
·
    Body, bonnet and valve plate (valve) material
    The valve body, bonnet and ram (valve) are one of the main components of the valve and are directly subjected to the medium pressure. The materials used must comply with the “pressure and temperature rating of the valve”. Common materials are as follows:
    1. Gray cast iron: Gray cast iron is suitable for water, steam, air, gas and oil media with a nominal pressure of PN ≤ 1.0 MPa and a temperature of -10 ° C to 200 ° C. The commonly used grades of gray cast iron are: HT200, HT250, HT300, HT350.
    2. Malleable cast iron: suitable for water, steam, air and oil media with nominal pressure PN ≤ 2.5MPa and temperature -30 ~ 300 °C. Commonly used grades are: KTH300-06, KTH330-08, KTH350-10.
    Third, ductile iron: suitable for PN ≤ 4.0MPa, temperature -30 ~ 350 ° C water, steam, air and oil and other media. Commonly used grades are: QT400—15, QT450—10, QT500—7. In view of the current state of the art, the factories are uneven, and users are often difficult to test. According to experience, it is recommended that PN ≤ 2.5MPa, the valve is still safe with steel valves.
    4. Acid-resistant high-silica ductile iron: suitable for corrosive media with nominal pressure PN≤0.25MPa and temperature below 120°C.
    5. Carbon steel: It is suitable for water, steam, air, hydrogen, ammonia, nitrogen and petroleum products with nominal pressure PN≤32.0MPa and temperature -30～425°C. Commonly used grades are WC1, WCB, ZG25 and high quality steel 20, 25, 30 and low alloy structural steel 16Mn.
    6. Copper alloy: suitable for water, seawater, oxygen, air, oil and other media with PN≤2.5MPa, and steam medium with temperature of -40～250°C. Commonly used grades are ZGnSn10Zn2 (tin bronze), H62, Hpb59-1 (Brass), QAZ19-2, QA19-4 (aluminum bronze).
    7. High temperature copper: suitable for steam and petroleum products with nominal pressure PN≤17.0MPA and temperature ≤570°C. Commonly used grades are ZGCr5Mo, 1Cr5M0. ZG20CrMoV, ZG15Gr1Mo1V, 12CrMoV, WC6, WC9 and other grades. The specific selection must be in accordance with the valve pressure and temperature specifications.
    Eight, low temperature steel, suitable for nominal pressure PN ≤ 6.4Mpa, temperature ≥ -196 °C ethylene, propylene, liquid natural gas, liquid nitrogen and other media, commonly used brands) ZG1Cr18Ni9, 0Cr18Ni9, 1Cr18Ni9Ti, ZG0Cr18Ni9
    Nine, stainless acid-resistant steel, suitable for nominal pressure PN ≤ 6.4Mpa, temperature ≤ 200 ° C nitric acid, acetic acid and other media, commonly used brands are ZG0Cr18Ni9Ti, ZG0Cr18Ni10 <nitrate resistant>, ZG0Cr18Ni12Mo2Ti, ZG1Cr18Ni12Mo2Ti <acid and urea>