Babbitt lead-based alloy

Lead-based alloy, also known as lead-based Babbitt metal, is a type of bearing alloy primarily composed of lead and antimony. Its room-temperature microstructure consists of a soft matrix of α solid solution (antimony dissolved in lead) with hard particles of β phase (lead dissolved in antimony) distributed throughout. To enhance strength, hardness, and wear resistance, 6% to 16% tin is typically added. To prevent specific gravity segregation, 1% to 2% copper is often incorporated. Additionally, small amounts of arsenic and cadmium can be added to refine the microstructure and improve the high-temperature hardness of the alloy. Compared to tin-based bearing alloys, lead-based alloys have lower strength, hardness, wear resistance, and impact toughness. They are usually manufactured as double or triple-layer metal structures and are used as bearings for low-speed, low-load, or medium-load applications under static conditions, as well as for high-speed, low-load bearings operating at temperatures below -150°C. Common grades include ZChPbSb16-16-2, ZChPbSb15-5-3, and ZChPbSb15-10. These alloys are produced via melting methods.

Lead-based bearing alloys are lead-antimony-tin-copper alloys with moderate hardness, good run-in properties, a slightly higher friction coefficient, and very low toughness. As a result, they are suitable for casting bushings subjected to minimal vibration, lighter loads, or slower speeds. They are primarily used in cables, batteries, and other applications.

Tin-based Babbitt metal—also known as tin alloy; examples include ZCHSnSb11-6, ZCHSnSb4-4, and ZCHSnSb8-4—is suitable for high-horsepower turbines, compressors, turbine pumps, high-speed internal combustion engines, ball mills, and various mineral processing equipment bearings. Tin serves as the base of the alloy, while copper, antimony, and lead act as alloying elements. The microstructure of this alloy consists of a soft matrix with hard particles. During operation of sliding bearings, the hard particles in the matrix support the bearing and withstand friction, while the soft matrix ensures good compatibility between the bearing and the journal. Therefore, both tin-based and lead-based Babbitt metals are ideal materials for casting mechanical bushings, sleeves, and liners, as well as for filling applications in mechanical seals, rigging fasteners, machine tool sliding pads, and grinding machine supports. Bearing alloys, also known as bush alloys, feature a microstructure with hard particles uniformly distributed in a soft matrix or soft particles in a hard matrix. These alloys exhibit excellent wear resistance and anti-friction properties, certain compressive strength and hardness, sufficient fatigue strength and load capacity, good plasticity and impact toughness, excellent anti-seizure properties, good conformity, and embeddability. They also possess superior thermal conductivity, corrosion resistance, and low thermal expansion coefficients, making them widely used in various sliding bearing wear-resistant materials.