ANALYSIS OF ANTI-FRICTION CHARACTERISTICS AND WORKABILITY OF THE WELD DEPOSITION OF COMPOSITE BRONZES REINFORCED BY STEEL DENDRITES

Abstract

The authors conducted comparative tribological tests (the coefficient of friction and the wear rate) on a group of anti-friction coatings from bronzes BrO10 produced by casting, BrKMts 3-1, Al bronze DT-CuAl8 and BrZhNA 12-7-1 produced by the weld deposition in argon with solid or powder wire, and babbitts B83 and B88 produced by gas torch surfacing in propane-butane flame, plasma spraying, arc metallization. Formation of dendrites in bronze BrZhNA 12-7-1 was found within a wide range of cooling speeds characteristic of main processes of producing anti-friction alloys: casting, weld deposition, spraying. The degree of dispersion of a dendritic component formed during the weld deposition process is significantly higher as compared with casting, ensuring an increase in strength of deposited metal by 30–50%. It has been shown that in conditions of boundary and fluid friction (РР = 1 MPa, V = 3 m/s, distance of friction is 100 km), wear of coatings from composite bronze BrZhNA 12-7-1 produced by the weld deposition is by 1.5–3 times lower than coatings from other typical anti-friction materials: babbitts (B83, B88), tin (BrO10) and tinless bronzes (BrKMts 3-1, DT-CuAl8) produced by the weld deposition and gas thermal spraying methods. The coefficient of friction of coatings from bronze BrZhNA 12-7-1 at 4.5 MPa is the same as for babbitt B83 and tin bronze BrO10. The conducted comparative tests indicate that argon arc welding of bronze BrZhNA 12-7-1 deposited on the steel base is workable enough both in the weld deposition without using intermediate layers and elimination of defects of intergranular penetration of copper in the steel base, when depositing bronzes. The authors are grateful to E. P. Zavarzina (Junior Researcher, Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences) for her support of conducting structural studies, and S. P. Kochugov (Director of LLC NPP TSP) for his support of preparing coated samples for studies. The research was conducted as part of the state order of the Ministry of Education and Science of Russia (subject: Structure, No. 122021000033-2). © 2024, Ore and Metals Publishing house. All rights reserved.