A New Cast Aluminium-Lead Bearing Alloy for Automobile Industry

摘要

In this study, A new foundry technique has been developed in which the more lead can be delivered into the molten aluminium alloy, followed by casting the alloys with the convention casting method. In order to investigated the lead content effects, 5 percent Pb, 10 percent Pb and 25 percent Pb were added into the Al alloys. In order to study the cooling velocity influence, the molten Al-Pb alloy was poured into copper, iron and different size sand moulds. The effects of the cooling velocity, the lead content and the gravity on the microstructures of Al-Pb alloy were discussed based on the results of optical microscope, SEM and quantitative metallography. The current experimental results show: 1) The shapes of th lead particles existed in the alloy are nearly round with different sizes. 2) The dimension of lead particles in the alloy varies with the lead content. And the average diameter of lead particles is 15mu for 5 percent Pb, 20mu for 10 percent Pb, and 30mu for 25 percent Pb respectively. 3) There is no evidence of lead segregation when the cooling velocity is reached 70 deg C/min. 4) The size of lead particles increase as the cooling velocity decreases. The gravity, however, has no significant effect on the lead distributions.