Commonly Used Materials And Usage Conditions of Valve Seals

Valve sealing ring materials are divided into two categories: metal and non-metal. Commonly used materials and their usage conditions are as follows:

1. Synthetic rubber

The comprehensive properties of synthetic rubber such as oil resistance, temperature resistance, and corrosion resistance are better than those of natural rubber. Generally, the operating temperature of synthetic rubber is t ≤ 150°C, and that of natural rubber t ≤ 60°C. The rubber is used for sealing of stop valves, gate valves, diaphragm valves, butterfly valves, check valves, pinch valves and other valves with a nominal pressure PN ≤ 1MPa.

2. Nylon

Nylon has the characteristics of small friction coefficient and good corrosion resistance. Nylon is mostly used in ball valves, stop valves, etc. with a temperature t ≤ 90°C and a nominal pressure PN ≤ 32MPa.

3. Polytetrafluoroethylene

PTFE is mostly used in stop valves, gate valves, ball valves, etc. with a temperature t ≤ 232°C and a nominal pressure PN ≤ 6.4MPa.

4. Cast iron

Cast iron is used for gate valves, globe valves, plug valves, etc. with temperature t ≤ 100°C, nominal pressure PN ≤ 1.6MPa, gas and oil.

5. Babbitt alloy

Babbitt alloy is used for ammonia stop valves with temperature t -70~150℃ and nominal pressure PN ≤ 2.5MPa.

6. Copper alloy

Commonly used copper alloy materials include 6-6-3 tin bronze and 58-2-2 manganese brass. Copper alloy has good wear resistance and is suitable for water and steam with temperature t ≤ 200℃ and nominal pressure PN ≤ 1.6MPa. It is often used in gate valves, globe valves, check valves, plug valves, etc.

7. Chromium stainless steel

Commonly used grades of chromium stainless steel include 2Cr13 and 3Cr13, which have good corrosion resistance after quenching and tempering treatment. It is commonly used in valves for media such as water, steam and petroleum with a temperature t ≤ 450°C and a nominal pressure PN ≤ 32MPa.

8. Chromium-nickel-titanium stainless steel

The commonly used grade of chromium-nickel-titanium stainless steel is 1Cr18Ni9ti, which has good corrosion resistance, erosion resistance and heat resistance. Suitable for steam, nitric acid and other media with temperature t ≤ 600℃ and nominal pressure PN ≤ 6.4MPa, and used in stop valves, ball valves, etc.

9. Nitrided steel

The commonly used grade of nitrided steel is 38CrMoAlA, which has good corrosion resistance and scratch resistance after carburizing treatment. Commonly used in power station gate valves with temperature t ≤ 540℃ and nominal pressure PN ≤ 10MPa.

10. Boronization

Boronizing directly processes the sealing surface from the valve body or valve body material, and then performs boronizing surface treatment. The sealing surface has very good wear resistance. Used for power station blowdown valves.