What materials are generally used for pump plain bearings?

Sliding bearing materials for pumps are mainly divided into two categories: metal materials and non-metallic materials. Picture metal materials Commonly used metal materials for plain bearings are bearing alloy (also called Barnes or white alloy), wear-resistant cast iron, copper-based and aluminum-based alloys. 1, bearing alloy Bearing alloy (also called Bachmann alloy or white alloy) main alloy composition is tin, lead, antimony, copper. Antimony, copper, to improve the alloy strength and hardness. According to the standard, the pasteurized alloy can be divided into tin-based alloy and lead-based alloy two kinds. The strength and hardness of lead-based alloy is lower than that of tin-based alloy, and the corrosion resistance is also poor. Therefore, when using pasteurized alloys, tin-based alloys are usually chosen, and their commonly used grades are ZSnSb11Cu6, ZSnSb8Cu4 and so on. Although the performance of lead-based alloy is not as good as that of tin-based alloy, but because it is more economical, it is still chosen to be used under the working conditions to meet the requirements, and its commonly used grades are ZPbSb16Sn16Cu2 and so on. However, the melting point of the bearing alloy element is mostly low, so it is suitable for working conditions below 150 ℃. 2, copper-based alloys Copper-based alloys have high thermal conductivity and better wear resistance than steel. And copper-based alloy has a very good processing and lubrication, its inner wall can be fine-tuning, and shaft smooth surface contact. 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 alloys have high strength, good thermal conductivity and wear resistance, and a higher allowable working temperature than Barnes' alloys, but are not as compliant, embedded, or friction-compatible as Barnes' alloys. Commonly used tin bronze containing tin and phosphorus, suitable for medium-speed heavy load or shock load bearing; tin bronze containing tin, zinc and lead, suitable for medium-speed medium load bearing. Pictures of non-metallic materials 1, PTFE has good self-lubricating properties and high thermal stability. Its friction factor is small, non-absorbent, non-sticky, non-combustible, can be used in -180 ~ 250 ℃ conditions. However, there is also a large coefficient of linear expansion, poor dimensional stability, poor thermal conductivity and other shortcomings. In order to improve its performance, available metal particles, fibers, graphite and inorganic filler reinforcement. Picture 2, graphite is a good self-lubricating material, and because it is easy to process, and the more grinding the smoother, so it is the choice of bearing materials. However, its mechanical properties are poor, poor impact resistance and load bearing capacity, only for light load occasions. In order to improve its mechanical properties, commonly used in some wear-resistant fusible metal for impregnation. Commonly used impregnation materials are Barnes alloy, copper alloy and antimony alloy. Dip Barnes alloy graphite bearings allow the use of the temperature of 120 ~ 180 ℃, dip copper alloy graphite bearings allow the use of the temperature of 300 ℃, dip antimony alloy graphite bearings allow the working temperature of up to 500 ℃. 3, rubber is a polymer with elastomer, has good elasticity and vibration absorption. But its poor thermal conductivity, processing difficulties, the permissible operating temperature of 65 ℃ or less, and the need to circulate water constantly lubricated cooling, so the general rarely used. 4, cemented carbide has high hardness, wear resistance, strength and toughness, heat resistance, corrosion resistance and other series of good performance, therefore, with its processing of sliding bearings with high precision, smooth operation, high hardness, good strength, durable, but expensive. 5, silicon carbide is a kind of synthetic new inorganic non-metallic materials. Hardness second to diamond, with good chemical corrosion resistance, wear resistance, high temperature performance and high mechanical strength, self-lubricating properties, high temperature creep resistance, small friction factor, high thermal conductivity, low coefficient of thermal expansion, etc., can be widely used in petroleum, metallurgy, chemical industry, machinery, aerospace and nuclear energy and other fields, commonly used as sliding bearings, as well as mechanical seals, friction sub-materials. A large number of tests show that silicon carbide is currently an excellent material in the friction sub-materials, especially pressureless sintered SiC and hot pressure sintered SiC performance is good.