FeCu Prealloyed Powder For Oil-retaining Bearing

Oil-retaining bearing was a kind of sliding bearing prepared by powder metallurgy method which could supply oil itself by impregnating oil in its pole. Oil-retaining bearing was widely used in fields such as transportation machine, household etc. The traditional raw materials of Fe-Cu oil-retaining bearing were reduced iron powder, electrolytic copper powder and additive. The traditional method to producing oil-retaining was a process of mixing, compacting, sintering, plasticing and oil impregnating which may led to composition segregation of raw material during transportation and applying. Therefore, developing raw material for Fe-Cu bearing with high performance has certain significance.Prealloyed powder of which titular composition was FeCu25 was studied in this paper. The influence of raw material species, diffusion temperture and diffusion time on microcosmic morphology, phisical properties, and sintered properties of prealloyed powder were studied in this paper. Oil-retaining bearing was prepared by prealloyed powder to investigate on sintered density. Mixing FeCu25 prealloyed powder with reduced iron powder, graphite powder and lubricant to compare properties with blended powder and foreign power of the same composition.The results showed that the microcosmic morphology of FeCu25 prealloyed powder prepared by direct reduced iron powder and modified ultrafine copper powder was spongy, the surface of iron particle was rough, the shape of copper particle bonded on iron particle surface was irregular. The microcosmic morphology of prealloyed powder was similar to foreign powder. Improving diffusion temperature from 800℃ to 950℃ or improving diffusion time from 3h to 6h led to increasing of particle size, apparent density, oil content, enhancing of flowability as well as reducing of oxygen content, sintered density, radial sintered dimensional change rate, radial crushing strength.FeCu25 prealloyed powder with diffusion temperature of 900℃ and diffusion time of 6h was prepared in this paper. The flowability, apparent density, oxygen content of FeCu25 powder was 27.85s·(50g)-1,2.56g·cm-3,0.29%. The radial direction sintered dimensional change rate, radial crushing strength, oil content of oil-retaining bearing was-0.385%,319.4MPa,21.7% while the compact density was 6.20g·cm-3 as well as the sintered density was 6.28g·cm-3. Compared with blended powder, FeCu25 bonded powder has excellent flowability and apparent density. The complexed properties of bonded powder was equivalent with foreign powder.This paper prepared Fe-20Cu-1.2C prealloyed powder by mixing FeCu25 prealloyed powder with reduced iron powder, graphite powder and Amid Wax. The flowability, apparent density, oxygen content of Fe-20Cu-1.2C powder was 35.03s·(50g)-1,2.60g·cm-3, 0.31%. The axial direction sintered dimensional change rate, radial direction sintered dimensional change rate, radial crushing strength, rockwell hardness of oil-retaining bearing was -0.171%,-0.043%,283.0MPa, HRB24.6 while the compact density was 6.10g·cm-3 as well as the sintered density was 6.16g·cm-3. Compared with blended powder, Fe-20Cu-1.2C bonded powder has excellent flowability and apparent density, the distribution of Cu element of bonded powder was more uniform. The complexed properties of bonded powder was equivalent with foreign powder.