The material of the sliding bearing is mainly non-ferro […]
The material of the sliding bearing is mainly non-ferrous metal. Commonly used are tin-based bearing alloys, lead-based bearing alloys, copper-based bearing alloys, aluminum-based bearing alloys, and the like.
(1) Tin-based bearing alloy (tin-based babbitt). It is an alloy composed of elements such as bismuth and copper. This alloy has a small friction coefficient and good plasticity and thermal conductivity. It is an excellent antifriction material and is often used as an important bearing, such as high-speed bearings for giant machines such as steam turbines, engines, and compressors. Its main disadvantage is that the fatigue strength is low and the tin is scarce, so the bearing alloy is the most expensive.
(2) Lead-based bearing alloys (lead-based babbitt). It is a lead-bismuth based alloy. The addition of tin can form a SnSb hard spot and can be dissolved in lead in a large amount to strengthen the matrix, thereby improving the strength and wear resistance of the lead-based alloy. The addition of copper forms a Cu2Sb hard spot and prevents segregation of specific density. Lead-based bearing alloys, lead-based bearing alloys have lower strength, ductility, thermal conductivity and corrosion resistance than tin-based alloys, and the friction coefficient is larger; but the price is cheaper. Therefore, lead-based bearing alloys are commonly used to manufacture medium-speed bearings that withstand medium and low loads, such as crankshafts, connecting rod bearings, and motor bearings for automobiles and tractors.