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Valve sealing ring materials are metal and non-metal two categories. Common materials and their conditions of use are as follows:
1. Synthetic rubber
Synthetic rubber is better than natural rubber in oil resistance, temperature resistance and corrosion resistance. General synthetic rubber use temperature t≤150℃, natural rubber t≤60℃, rubber is used for nominal pressure PN≤1MPa globe valve, gate valve, diaphragm valve, butterfly valve, check valve, pinch valve and other valves seal.
2. Nylon
Nylon has the characteristics of low friction coefficient and good corrosion resistance. Nylon is used for ball valves and globe valves with temperature t≤90℃ and nominal pressure PN≤32MPa.
3. Teflon
Polytetrafluoroethylene is widely used in globe valves, gate valves and ball valves with temperature t≤232℃ and nominal pressure PN≤6.4MPa.
4. Cast iron
Cast iron is used for gate valve, globe valve, plug valve and so on for gas and oil, temperature t≤100℃, nominal pressure PN≤1.6MPa.
5. Babbitt alloy
Babbitt alloy for temperature t-70~150℃, nominal pressure PN≤2.5MPa ammonia globe valve.
6. Copper alloy
Copper alloys commonly used materials are 6-6-3 tin bronze and 58-2-2 manganese brass. Copper alloy wear resistance is good, suitable for temperature t≤200℃, nominal pressure PN≤1.6MPa water and steam, often used in gate valve, globe valve, check valve, plug valve, etc.
7. Chrome stainless steel
Chrome stainless steel commonly used grade 2Cr13, 3Cr13 after conditioning treatment, good corrosion resistance. Often used in the temperature t≤450℃, nominal pressure PN≤32MPa of water, steam and oil and other medium valve.
8. Chrome-nickel titanium stainless steel
Inconel titanium stainless steel commonly used for 1Cr18Ni9ti, its corrosion resistance, erosion resistance and heat resistance is good. Suitable for temperature t≤600℃, nominal pressure PN≤6.4MPa steam, nitric acid and other media, for globe valves, ball valves, etc.
9. Nitriding steel
The common grade of nitriding steel is 38CrMoAlA. After carburizing, it has good corrosion resistance and abrasion resistance. It is commonly used in power station gate valves with temperature t≤540℃ and nominal pressure PN≤10MPa.
10. Boriding
Boronized sealing surface is directly processed by the body or valve disc body material, and then boronized surface treatment, sealing surface wear resistance is good. For power plant blowdown valve.
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