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Brief introduction of commonly used valve sealing surface materials

First, the soft sealing material
(1) Butadiene rubber (NBR). Butadiene rubber has excellent oil resistance; heat resistance is superior to natural rubber and styrene-butadiene rubber; air tightness and water resistance are good. Butadiene rubber can be divided into Dingjing-18, Dingjing-26 and Dingjing-40. Phase rubber is suitable for petroleum products with temperature -60~+120 degrees, benzene, toluene, water, acid and alkali medium.
(2) Fluororubber (FKM). Fluororubber is heat-resistant, acid-base resistant, oil-resistant, saturated water and steam, with small compression set and good air tightness. Fluororubber is suitable for petroleum products, water, acid and alcohol with a temperature of -30 to +220 degrees.
(3) Polytetrafluoroethylene (PTFE). PTFE is resistant to high temperature, chemical corrosion, and low friction coefficient, but has low mechanical strength, is easy to creep, and has low elasticity. It is suitable for corrosive media with a temperature equal to 170 degrees.
(4) Polytetrafluoroethylene (PTFE). PTFE is resistant to high temperature, chemical corrosion, and low friction coefficient, but has low mechanical strength, is easy to creep, and has low elasticity. It is suitable for corrosive media with a temperature of 170 degrees or less.

Second, hard sealing materials
(1) Copper alloy. Copper alloy has good corrosion resistance and wear resistance in water or steam. It is suitable for medium with PN≤1.6MPa and temperature not exceeding 200°. It can be fixed on the body by insert ring structure or surfacing and casting. . Commonly used grades are ZCuAl10Fe3 (aluminum bronze), ZCuZn38Mn2Pb2 (cast brass).
(2) Chrome stainless steel. Chromium stainless steel has good corrosion resistance and is commonly used in water, steam and oil, and media with a temperature not exceeding 450 degrees. Commonly used grades are 2Cr13, 1Cr13.
(3) Stellite alloy. Stellite carbide corrosion resistance. It has excellent comprehensive properties such as erosion resistance and scratch resistance. It is suitable for various kinds of valves and temperatures of -268 to +650 degrees, especially for highly corrosive media. One of the ideal sealing surface materials. Because of the high price, Stellite alloys use surfacing.
(4) Nickel base alloy. Nickel-based alloys are another important material in the field of corrosion resistance. There are three types of sealing surface materials commonly used: Monel, Hastelloy B and Hastelloy C. Monel is the main material for the resistance to hydrofluoric acid corrosion. It is suitable for alkali, salt, food and air-free acid solvent media at temperatures from -240 to +482 °C. Hastelloy B and Hastelloy C are the most comprehensive corrosion-resistant materials in valve sealing surface materials. They are suitable for corrosive mineral acids, sulfuric acid, phosphoric acid, wet HCI gas and strong oxidizing medium with temperature of 371 degrees (hardness 14RC). At the same time, it is suitable for non-chloric acid solution and strong oxidizing medium at 538 °C (23 RC).
(5) Iron-based alloys. Iron-based alloy is a newly developed sealing surface material in China. Its wear resistance and scratch resistance are better than 2Cr13, and it has certain corrosion resistance and can replace 2Cr13. Suitable for non-corrosive media with a temperature of 450 degrees or less. Commonly used grades are WF311, WF312 iron-based powder.

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