Effect of Cu alloy element on the performance of powder metallurgy surface rolling densification

Rolling densification process is widely used in manufacture field of powder metallurgy gears, which could reduce the noise and enhance the rolling contact fatigue performance of gears. The original composition of powder metallurgy blank parts has a significant effect on the performance of surface rolling densification. The effect of Cu content by mass on rolling densification was studied in this paper, the influences of raw materials on porosity, structure, hardness, and wearing resistance of powder metallurgy gears in the surface rolling densification process were analyzed and discussed. The results show that, Cu plays an important role on the densification behavior and the properties of powder metallurgy gear parts. Under the same rolling parameters, the parts with lower Cu content have better surface densification performance because of the lower degree of alloying. However, the increase of Cu content is conducive to improve the hardness and wearing resistance of the parts. The parts with 1.4% Cu by mass have the surface dense layer in 1.13 mm and show the high wearing resistance, which have the best overall performance and are more suitable for the actual working conditions applications.