EPEN Technology Knowledge: What materials are commonly used for sliding bearings for pumps?

  • Sliding bearing materials for water pumps are mainly divided into metal materials and non-metal materials.

Sliding bearing materials for water pumps are mainly divided into metal materials and non-metal materials.

 

 

Metallic materials

 

Common sliding bearing metal materials include bearing alloy (also known as Babbitt alloy or white alloy), wear-resistant cast iron, copper based and aluminum based alloys.

 

1. Bearing alloy

The main alloy components of bearing alloy (also known as Babbitt alloy or white alloy) are tin, lead, antimony and copper. Antimony and copper are used to improve the strength and hardness of alloys. According to the standard, Babbitt alloy can be divided into tin based alloy and lead based alloy. The strength and hardness of lead based alloy are lower than that of tin based alloy, and the corrosion resistance is also poor. Therefore, when using Babbitt alloy, tin based alloy is usually selected, and its commonly used brands are ZSnSb11Cu6, zsnsb8cu4, etc. Although the performance of lead based alloy is not as good as that of tin based alloy, it is relatively economical, so it is still used under the working conditions that meet the requirements. Its commonly used brands include zpbsb16sn16cu2, etc. However, the melting point of bearing alloy elements is mostly low, so it is suitable for working conditions below 150 ℃.

 

2. Copper base alloy

Copper based alloys have higher thermal conductivity and better wear resistance than steel. And the copper base alloy has good machinability and lubricity. Its inner wall can be precision machined and in contact with the smooth surface of the shaft. Copper based alloys used as sliding bearing materials mainly include: brass with copper and antimony as the main components; Bronze with copper and tin as the main components; And copper lead alloy (also known as lead bronze). Copper based alloy has high strength, good thermal conductivity and wear resistance, and the allowable working temperature is higher than Babbitt alloy, but its compliance, Embeddedness and friction compatibility are not as good as Babbitt alloy. Common tin bronze containing tin and phosphorus is suitable for bearings with medium speed, heavy load or impact load; Tin bronze containing tin, zinc and lead is suitable for bearings with medium speed and medium load.

 

 

Non metallic materials

 

1. Polytetrafluoroethylene

It has good self-lubricating performance and high thermal stability. Its friction coefficient is small, non absorbent, non sticky, non combustible, and can be used at -180~250 ℃. However, there are also some shortcomings, such as large linear expansion coefficient, poor dimensional stability, poor thermal conductivity and so on. In order to improve its performance, metal particles, fibers, graphite and inorganic substances can be used for filling and strengthening.

 

 

2. Graphite

It is a kind of good self-lubricating material, and because it is easy to process, and the more it is ground, the smoother it becomes, so it is the material of choice for bearings. However, due to its poor mechanical properties, impact resistance and load bearing capacity, it is only suitable for light load occasions. In order to improve its mechanical properties, some fusible metals with good wear resistance are usually impregnated. Commonly used impregnating materials include Babbitt alloy, copper alloy and antimony alloy. The allowable operating temperature of Babbitt graphite bearing is 120~180 ℃, the allowable operating temperature of copper alloy graphite bearing is 300 ℃, and the allowable operating temperature of antimony alloy graphite bearing can reach 500 ℃.

 

3. Rubber

It is a polymer made of elastomer, which has good elasticity and vibration absorption. However, due to its poor thermal conductivity, difficult processing, allowable service temperature below 65 ℃, and continuous lubrication and cooling of circulating water, it is generally rarely used.

 

4. Cemented carbide

It has high hardness, wear resistance, good strength and toughness, heat resistance, corrosion resistance and other good properties. Therefore, the sliding bearing processed with it has high precision, stable operation, high hardness, good strength and durability, but the price is expensive.

 

5. Silicon carbide

It is a new type of synthetic inorganic nonmetallic material. Its hardness is inferior to that of diamond. It has good chemical corrosion resistance, wear resistance, high temperature resistance, high mechanical strength, good self-lubricating performance, high temperature creep resistance, low friction coefficient, high thermal conductivity, low coefficient of thermal expansion. It can be widely used in petroleum, metallurgy, chemical industry, machinery, aerospace, nuclear energy and other fields, and is commonly used as friction pair material of sliding bearings and mechanical seals. A large number of tests show that silicon carbide is an excellent material in friction pairs at present, especially pressureless sintered SiC and hot pressed sintered SiC.

 

More about EPEN Multi-layer Sliding Bearings

Jiashan Epen Bearing Co., Ltd. is a professional manufacturer of sliding bearings, metal plastic composite bearings business, specializing in adhering to do fine, the better for our customers continue to create value concept, is committed Sliding Bearings, new composite materials research, development, promotion and applications. Company's existing main products for metal-plastic composite series Sliding Bearings, bimetal bearings, sliding bearings single metal series, are widely used in automotive, metallurgy, engineering machinery, construction machinery, plastics machinery, machine tool industry, water conservancy and hydropower 30 a number of areas.

 

 

 

E94 Bushing:

E94 is deriving from E93; the difference between E93 & E94 is Indentations on working surface, which substituted by Through-holes. Theses holes will allow greater capacity to collect lubricant, which build up a lubrication film at the start of movement and reduce the frication. It is suitable for high load, lower speed application .inery.

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