Sealing ring material and operating conditions

Valve sealing ring materials are metal and non-metal. Common materials and conditions are shown in table 7-6.

Table 7-6 common materials and operating conditions of sealing ring

Sealing surface material

Performance and operating conditions

Natural rubber

Synthetic rubber

Synthetic rubber is superior to natural rubber in oil, temperature and corrosion resistance. General use temperature of synthetic rubber t≤150℃,

Natural rubber t≤60℃, rubber for nominal pressure PN≤1MPa globe valve, gate valve, diaphragm valve, butterfly valve, check valve, clip valve and other valves seal

nylon

Nylon has the characteristics of low friction coefficient and good corrosion resistance. Nylon used for temperature t≤90℃, nominal pressure PN≤32MPa ball valve, stop valve, etc

polytetrafluoroethylene

Ptfe is mainly used for globe valves, gate valves and ball valves with temperature t≤232℃ and nominal pressure PN≤6.4MPa

Cast iron

Gate valve, globe valve and plug valve for temperature ≤100℃, nominal pressure PN≤1.6MPa, gas and oil, etc

babbitt

For ammonia globe valves with temperature t:-70 ~ 150℃ and nominal pressure PN≤2.5MPa

Copper alloy

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 of water and steam, commonly used in gate valve, globe valve, check valve, cock valve, etc

Chromium stainless steel

Common brands are 2Cr13, 3Cr13 after conditioning, corrosion resistance is good. Usually used for water, steam and oil medium valves with temperature t≤450℃ and nominal pressure PN≤32MPa

Chromium-nickel-titanium stainless steel

The commonly used brand is 1Cr18Ni9Ti, which has good corrosion resistance, erosion resistance and heat resistance. Suitable for steam, nitric acid and other medium with temperature t≤600℃ and nominal pressure PN≤6.4MPa

Nitriding steel

Common brand is 38CrMoAlA, carburized, with good corrosion resistance and abrasion resistance. It is often used for gate valve of power station with temperature t≤540℃ and nominal pressure PN≤10MPa

boronizing

The sealing surface is directly processed from the body material of valve body or valve disc, and then boronized surface treatment. Used for sewage valve of power station