Performs well in high-temperature applications. It has excellent corrosion resistance for highly corrosive fluid media.

General name and characteristics of valve material

1、 Grey cast iron: Grey cast iron is suitable for media such as water, steam, air, gas, and oil with a nominal pressure PN ≤ 1.0MPa and a temperature range of -10 ℃ to 200 ℃. The commonly used grades of gray cast iron are HT200, HT250, HT300, and HT350.

2、 Malleable cast iron: suitable for water, steam, air, and oil media with a nominal pressure PN ≤ 2.5MPa and a temperature of -30~300 ℃. Commonly used grades include KTH300-06, KTH330-08, and KTH350-10.

3、 Ductile iron: suitable for media with PN ≤ 4.0MPa and temperatures ranging from -30 to 350 ℃, such as water, steam, air, and oil. Commonly used brands include QT400-15, QT450-10, and QT500-7.
Given the current level of domestic technology and the uneven nature of various factories, it is often difficult for users to inspect. Based on experience, it is recommended to use steel valves for safety when PN ≤ 2.5MPa.

4、 Acid resistant high silicon ductile iron: suitable for corrosive media with nominal pressure PN ≤ 0.25MPa and temperature below 120 ℃.

5、 Carbon steel: suitable for media such as water, steam, air, hydrogen, ammonia, nitrogen, and petroleum products with a nominal pressure of PN ≤ 32.0MPa and a temperature of -30~425 ℃. Commonly used grades include WC1, WCB, ZG25, 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, as well as steam media with temperatures ranging from -40 to 250 ℃. Commonly used brands 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 ℃. Commonly used brands include ZGCr5Mo, 1Cr5M0. ZG20CrMoV, ZG15Gr1Mo1V, 12CrMoV, WC6, WC9, and other brands. The specific selection must comply with the regulations of valve pressure and temperature specifications.

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

9、 Stainless acid resistant steel: suitable for medium with nominal pressure PN ≤ 6.4Mpa, temperature ≤ 200 ℃ nitric acid, acetic acid, etc. Commonly used grades include ZG0Cr18Ni9Ti, ZG0Cr18Ni10, ZG0Cr18Ni12Mo2Ti, ZG1Cr18Ni12Mo2Ti

The relationship between valve material and temperature and pressure

1. Service temperature of the valve
The operating temperature of the valve is determined by the material used to manufacture the valve. The usage temperatures of commonly used materials for valves are as follows:

When using rubber or plastic for valve lining, the temperature resistance of the rubber or plastic shall prevail.
Ceramic valves, due to their poor temperature resistance and sudden change, are generally used for operating conditions below 150 ℃. Recently, a high-performance ceramic valve has emerged that can withstand high temperatures below 1000 ℃.
Glass valves have poor temperature resistance and are generally used under operating conditions below 90 ℃.
Enamel valves have temperature resistance limited by the sealing ring material, with a maximum operating temperature not exceeding 150 ℃.

2. Pressure used by the valve
The service pressure of the valve is determined by the material used to manufacture the valve.

3. The relationship between valve temperature and pressure

The temperature and pressure of valve use have a certain internal connection and mutual influence. Among them, temperature is the dominant factor affecting the valve. Valves with a certain pressure are only suitable for a certain temperature range, and changes in valve temperature can affect the valve's operating pressure.
For example, if the nominal pressure of a carbon steel valve is 10MPa, and the working temperature of the medium is 200 ℃, the maximum working pressure P20 is 10MPa; When the working temperature of the medium is 400 ℃, its maximum working pressure P40 is 5.4MPa; When the working temperature of the medium is 450 ℃, its maximum working pressure P20 is 4.5MPa.