Machinability of Copper Sulfide-Dispersed Lead-Free Bronze

Abstract

Molybdenum sulfide (MoS₂) was added to molten bronze consisting of Cu and Sn. Then, the machinability of the obtained bronze was examined from the viewpoints of cutting force, chip disposability and finished surface roughness. Copper sulfide (Cu₂S)-dispersed bronze is produced by adding MoS₂ to molten bronze. The dispersion of Cu₂S reduces the coefficient of friction on the rake surface and increases the shear angle, resulting in a decrease in cutting force. The Cu₂S-dispersed bronze has a good chip disposability because Cu₂S acts as a chip breaker. The dispersion of Cu₂S has no influence on the finished surface roughness. Thus, the Cu₂S-dispersed bronze has an excellent machinability equivalent to those of CAC406 containing Pb and CAC902 containing Bi.