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Valve gasket installation and material selection

2022-10-31
1、Carbon steel
The recommended maximum operating temperature is not more than 538℃, especially when the medium is oxidizing. High quality thin carbon steel plates are not suitable for equipment used to manufacture inorganic acid, neutral or acidic salt solutions. If carbon steel is stressed, the accident rate of equipment used in hot water working conditions is very high. Carbon steel gaskets are usually used in high concentrations of acid and many alkali solutions. Brinell hardness is about 120.
2、304 stainless steel
18-8(chromium 18-20%, nickel 8-10%), the recommended maximum operating temperature is not more than 760℃. In the temperature range of -196~538℃, stress corrosion and grain boundary corrosion are easy to occur. Brinell hardness 160.
3、304 l stainless steel
The carbon content is not more than 0.03%. The recommended maximum operating temperature is not higher than 760 ° C. Corrosion resistance similar to 304 stainless steel. The low carbon content reduces the carbon precipitation from the lattice, and the grain boundary corrosion resistance is higher than 304 stainless steel. The Brinell hardness is about 140.
4、316 stainless steel
18-12(chromium 18%, nickel 12%), in 304 stainless steel increase about 2% molybdenum, when the temperature increases its strength and corrosion resistance is improved. When the temperature is increased, it has higher creep resistance than other ordinary stainless steels. The recommended maximum operating temperature is not higher than 760 ° C. The Brinell hardness is about 160.
5、316 l stainless steel
The recommended maximum continuous operating temperature ranges from 760 ° C to 815 ° C. Compared with 316 stainless steel, it has better resistance to stress and grain boundary corrosion with carbon content not exceeding. The Brinell hardness is about 140.
6、20 alloy
45% iron, 24% nickel, 20% chromium and small amounts of molybdenum and copper. The recommended maximum operating temperature ranges from 760 ° C to 815 ° C. Especially suitable for the manufacture of sulfuric acid corrosion resistant equipment, Brinell hardness of about 160.
7、aluminum
Aluminum (not less than 99%). Aluminum has excellent corrosion resistance and machining properties, suitable for the manufacture of double gaskets. The Brinell hardness is about 35. The recommended maximum continuous operating temperature is 426 ° C.
8、copper
The composition of red copper is close to pure copper, and it contains a trace of silver to increase its continuous operating temperature. The recommended maximum continuous operating temperature is 260 ° C or less. The Brinell hardness is about 80.
9、brass
(copper 66%, zinc 34%), under most working conditions, with good corrosion resistance, but not suitable for acetic acid, ammonia, salt and acetylene. The recommended maximum continuous operating temperature is 260 ° C or less. The Brinell hardness is about 58.
10、Hartz - 2 B
(26-30% molybdenum, 62% nickel and 4-6% iron). The recommended maximum operating temperature is 1093 ° C. It has excellent resistance to heat concentration hydrochloric acid corrosion. It also has excellent resistance to wet hydrogen chloride gas corrosion, sulfuric acid, phosphoric acid and reducing salt solution corrosion performance. High strength at high temperature. The Brinell hardness is about 230.
11、Hartz C - 276
16-18% molybdenum, 13-17.5% chromium, 3.7-5.3% tungsten, 4.5-7% iron, and the rest are nickel). The recommended maximum operating temperature is 1093 ° C. It has excellent corrosion resistance. It has excellent corrosion resistance to all kinds of cold nitric acid or boiling nitric acid with a concentration of 70%. It has good resistance to hydrochloric acid and sulfuric acid corrosion and excellent resistance to stress corrosion. The Brinell hardness is about 210.
12、The Incornel 600
Nickel base alloy (77% nickel, 15% chromium and 7% iron). The recommended maximum operating temperature is 1093 ° C. High strength at high temperatures and is commonly used in equipment where stress corrosion problems are to be solved. At low temperature, it has excellent same processing performance. Brinell hardness is about 150.
13、Monel 400
(For copper 30% and nickel, the recommended maximum continuous operating temperature is not more than 815℃. It has excellent corrosion resistance to most acids and bases except for strong oxidizing acids. It is easy to produce stress corrosion cracks in fluoric acid, mercuric chloride and mercuric media, so it is not suitable for the above media. Is widely used in the manufacture of hydrofluoric acid equipment. Brinell hardness is about 120.
14、titanium
The recommended maximum operating temperature is 1093 ° C. Excellent corrosion resistance at high temperature. It is known to be resistant to chloride ion erosion, and has excellent resistance to nitric acid corrosion in a wide range of temperature and concentration. Titanium is rarely used in most alkali solutions and is suitable for oxidizing conditions. The Brinell hardness is about 216.
Non-metallic gasket material
1、Natural rubber NR
t has good corrosion resistance to weak acid and alkali, salt and chloride solution, but poor corrosion resistance to oil and solvent, so it is not recommended to be used in ozone medium. The recommended operating temperature is -57 ° C to 93 ° C.
2、Neoprene CR
Neoprene is a synthetic rubber that is resistant to moderately corrosive acid, alkali and salt solutions. Good corrosion resistance to commercial oils and fuels. However, the corrosion resistance of strong oxidizing acids, aromatic hydrocarbons and chlorinated hydrocarbons is poor. Recommended operating temperature -51 ° C to 121 ° C.
3、Butadiene rubber NBR
Cyanobutadiene rubber is a synthetic rubber suitable for a wide temperature range with good corrosion resistance to oils, solvents, aromatic hydrocarbons, basic hydrocarbons, petroleum and natural gas. It has good corrosion resistance to hydroxides, salts and near neutral acids. However, its corrosion resistance is poor in strong oxidizing media, chlorinated hydrocarbons, ketones and lipids, and the recommended operating temperature is 51℃~121℃.
4、Fluorine rubber
It has good corrosion resistance to oil, fuel, chloride solution, aromatic hydrocarbons and lipid hydrocarbons and strong acids, but it is not suitable for amines, lipids, ketones and steam. The recommended operating temperature is -40℃~232℃.
5、Chlorosulfonated polyethylene synthetic rubber
It has good corrosion resistance to acid, alkali and salt solutions, and is not affected by climate, light, ozone, commercial fuels (such as diesel and kerosene). However, it is not suitable for aromatic hydrocarbons, chlorinated hydrocarbons, chromic acids and nitric acids. Recommended operating temperature -45 ° C to 135 ° C.
6、Silicone rubber
It has good corrosion resistance to hot air. Silicone rubber is protected from sunlight and ozone. However, it is not suitable for steam, ketones, aromatic hydrocarbons and lipid hydrocarbons.
7、Ethylene propylene rubber
It has good corrosion resistance to strong acid, alkali, salt and chloride solutions. However, it is not suitable for oils, solvents, aromatic hydrocarbons and hydrocarbons. The recommended operating temperature is -57 ° C to 176 ° C.
8、graphite
The material does not contain resin or inorganic graphite materials, can be divided into metal mixed or not mixed with metal elements graphite materials. The material can be bonded to make pipe gaskets over 600MM in diameter. Excellent corrosion resistance to many acids, bases, salts and organic compounds and heat transfer solutions, even high temperature solutions. It cannot melt, but will sublimate above 3316 ° C. At high temperature, the material should be used carefully in strong oxidizing media. In addition to gaskets, the material can also be used to make filler and non-metallic winding tape in wound gaskets.
9、Ceramic fiber, ceramic fiber formed on strip
It is an excellent gasket material suitable for high temperature and low pressure conditions and light flange conditions. The recommended operating temperature is 1093℃. It can be used to make non-metallic winding tape in winding gasket.
10、Polytetrafluoroethylene
Incorporates the advantages of most plastic gasket materials, including temperature resistance from -95 ° C to 232 ° C. In addition to free fluorine and alkali metals, it has excellent corrosion resistance to chemicals, solvents, hydroxides and acids. PTFE material can be filled with glass, the purpose of which is to reduce the cold flow and creep property of PTFE.
 
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