Materials and Classification of Sealing Ring in Common Use
Materials and Classification of sealing Ring in Common use
Guide reading: I believe you know very little about the material of the seal (seal ring), the original seal material can have so many kinds of material manufacturing technology, you know different sealing ring materials have his different medium resistance? Do you know which sealing materials are most commonly used? Today, one by one for everyone to decompose the sealing ring which several materials and different resistance to media bar.
Rubber seal (ring)
I, the most common sealing ring material and medium resistance.
1. Natural rubber (temperature 0-80) is suitable for drinking water, hot water, oil-free air, etc.
2, silicone rubber (temperature 70-260) is suitable for drinking water, hot water, oil free air and high temperature steam, etc.
EPDM (temperature 50-150) is suitable for hot water, dilute acid, oil-free air and many chemicals, not for petroleum medium.
4, nitrile butadiene rubber (temperature 30-85) is suitable for petroleum products, oily steam air, vegetable oil and mineral oil; not for hot water above 65 ℃ or hot dry air above 60 ℃.
5, fluorinated rubber (temperature 6-1480) is suitable for a variety of oxidized acids, petroleum, halogenated Jing, lubricating oil, hydraulic unit liquids, organic liquids and air containing carbides.
II, the most common rubber seals (sealing ring) material classification and application.
Rubber is one of the most common materials for making sealing rings. In addition, it also includes graphite, PTFE and various sealants. The sealing parts of rubber materials products (sealing rings) are common at home and abroad. The seals of general rubber materials (seals) are used in chemical industry, national defense, coal, transportation, petroleum, Metallurgical and mechanical manufacturing industries are more and more widely used to create the most common basic parts (accessories) in various industries.
1. The common materials of rubber sealing products are as follows: butadiene acrylonitrile rubber (NBR): therefore, oil-resistant sealing products and nitrile-butadiene rubber are mainly used. Acrylonitrile-butadiene rubber (NBR) has excellent properties such as fuel oil and aromatic solvent, but it is not resistant to ketone, ester and hydrogen chloride.
Chloroprene rubber: Chloroprene rubber also has good corrosion resistance to inorganic acids. In addition, because Chloroprene rubber also has good flexural and impermeability, can be made into diaphragm and vacuum sealing products. Chloroprene rubber has good oil resistance and solvent resistance. It has good resistance to gear oil and transformer oil, but not aromatic oil. Chloroprene rubber also has excellent weathering resistance and ozone aging performance. The crosslinking breakage temperature of Chloroprene rubber is above 200 ℃.
Natural rubber: compared with most synthetic rubber, natural rubber has good comprehensive mechanical properties, cold resistance, high resilience and wear resistance. Natural rubber is not resistant to mineral oil, but stable in vegetable oils and alcohols. In the hydraulic braking system of brake fluid composed of n-butanol and refined castor oil, the rubber ring is made of natural rubber, and the general sealant is also made of natural rubber.
Fluorine rubber: fluorine rubber with outstanding heat resistance (200 ℃ 250 ℃), oil resistance, can be used in the manufacture of cylinder sleeve sealing ring, rubber bowl and rotating lip seal ring, can significantly improve the service time.
Silicone rubber: silicone rubber with outstanding resistance to high and low temperature, ozone and weathering resistance, in the working temperature range of -70 ℃ 260 ℃ to maintain its unique use of elasticity and ozone resistance, weather resistance and other advantages, Suitable for making sealing gaskets needed in hot mechanism, such as strong light source lampshade sealing ring, valve pad, etc. Because silicone rubber is not oil-resistant, mechanical strength is low and price is high, it is not suitable to make oil-resistant sealing products.
Ethylene-propylene diene diethylene propylene diene EPDM has excellent aging resistance, ozone resistance, weathering resistance, heat resistance (can be used at 120 ℃ for a long time), chemical resistance (such as alcohol, acid, strong alkali, oxidant), but not fatty group and aromatic solvent erosion. Ethylene-propylene diene rubber has the lowest density in rubber with high filling characteristics, but it lacks self viscosity and mutual viscosity. In addition, ethylene-propylene diene rubber has outstanding steam resistance, and can be used to make steam resistant diaphragm and other sealing products. . EPDM has been widely used in washing machines, television accessories and door and window sealing products, or in the production of multiple compound profiles.
Polyurethane rubber: polyurethane rubber with excellent wear and gas permeability, the use of temperature range-20 ~ 80 ℃. In addition, it has medium oil resistance, oxygen resistance and ozone aging resistance, but not acid and alkali, water, steam and ketone. Suitable for making all kinds of rubber sealing products, such as oil seal, o-ring and diaphragm etc.
Chloroether rubber: it has the advantages of nitrile butadiene rubber, neoprene rubber and acrylate rubber. Its oil resistance, heat resistance, ozone resistance, flame resistance, alkali resistance, water resistance and organic solvent resistance are all very good. Its cold resistance is poor. In the use of low temperature, the use of ether rubber is still the manufacture of oil seals, all kinds of seals, gaskets, diaphragm and dust cover and other sealing products good materials.
Acrylic rubber: acrylic rubber with heat resistant oil (mineral oil, lubricating oil and fuel oil), especially at high temperature oil stability, generally up to 175 ℃, gap use or short time can withstand temperature 200 ℃. Its disadvantage is its poor cold tolerance. Therefore, it is suitable for making oil seals with high temperature resistance in non-cold areas, but not suitable for sealing products under tensile or compression stress at high temperature.
2, rubber seal application and medium resistance classification: NBR: oil resistance, heat resistance, wear resistance. Widely used in the manufacture of sealing products, but not suitable for phosphate series hydraulic and gear oil containing polar additives.-40 ~ 120 ℃, for making "O" ring, oil seal, suitable for general hydraulic and pneumatic systems.
Hydrogenated nitrile rubber: high strength, oil resistance, wear resistance, heat resistance, aging resistance.-40 ℃, for high temperature, high speed reciprocating seal and rotary seal.
Rubber and plastic adhesive: material with large modulus of elasticity, high strength, other properties, such as "O" ring, "Y" ring, dust-proof ring, etc., used in sealing of construction machinery and high pressure hydraulic system.
Fluorine rubber: heat, acid and alkali resistance and other chemicals, oil resistance (including phosphate series hydraulic oil), suitable for all lubricants, gasoline, hydraulic oil, synthetic oil.-20 ℃, suitable for high temperature resistance, chemicals, The seal of flammable hydraulic oil is widely used in metallurgy, electric power and other industries. Polyurethane: excellent wear resistance, high strength, good aging resistance.-2080 ℃. Suitable for high pressure and high speed system sealing in construction machinery and metallurgical equipment.
Silicone rubber: heat resistant, good cold resistance. Compression permanent deformation is small, but mechanical strength is low,-60 ℃ 230 ℃. It is suitable for high speed rotating seal and food machinery seal under high and low temperature.
Polyacrylic acid ester: heat resistance is superior to that of NBR, in lubricating oil, hydraulic oil and petroleum hydraulic oil containing polar additives, with poor water resistance.-20 ℃ 150 ℃. It can be used in various car oil seals and various gear boxes. Gearbox, can withstand medium and high temperature.
EPDM rubber: good weather resistance, aging resistance in air, general oil resistance, freon resistance and a variety of refrigerants. -50 ℃, used for sealing refrigerators and refrigeration machinery.
PTFE: chemical stability, heat resistance, cold resistance, oil resistance, water, steam, medicine and other media. High mechanical strength, high temperature resistance, wear resistance, very low friction coefficient, good self-lubricity. It is widely used in metallurgy, petrochemical, construction machinery and light industry machinery.
Nylon: oil resistance, heat resistance, good wear resistance, high compressive strength, good impact resistance, but poor dimensional stability.-40 ℃ 120 ℃, for making guide ring, support ring, pressure ring, ring.
Polyformaldehyde: oil resistance, heat resistance, wear resistance, high compressive strength, good impact resistance, good self-lubricating performance, good dimensional stability, but poor flexural. -4040 ℃. It is used to make guide ring and retaining ring.