Microstructures and Properties of Tin-Based Babbitt Metal Prepared by Laser Cladding Deposition

Tin-based Babbitt metals arc widely used as wear-resistant materials on the surface of high-performance bearing parts because of its low friction coefficient, good wear resistance and excellent anti-adhesion. To improve the defects in tin-based Babbitt alloy prepared by traditional casting and reduce material waste, laser cladding deposition (LCD) was used to fabricate tin-based Babbitt metal on the surface of 20 steel substrate, and the laser cladded Babbitt metal was compared with the alloys prepared by other two preparation processes, namely, the static casting and the centrifugal casting. The microstructure, element distribution, microhardness, friction and wear performance, and internal quality of the alloy layers were tested and analyzed. Results show that the microstructure size of tin-based Babbitt metal prepared by LCD is smaller than those of cast alloys, and the microstructure along the deposition direction is characterized by banded distribution of light alternated with darkness. Besides, the microhardness of the alloy layer prepared by LCD is significantly higher than that of the alloy prepared by static casting process and similar to that of the alloy prepared by centrifugal casting process. Nevertheless, in the case of dry friction, the friction coefficient of tin-based Babbitt metal prepared by LCD is greater than that of the alloys prepared by traditional casting process, and its wear mechanism is mainly abrasive wear. Additionally, ultrasonic and dye-penetration nondestructive tests indicate that there arc no obvious defects in the tin-based Babbitt metal layer prepared by LCD, and it is well bonded to the steel back.