Research On Squeeze Casting Technology For High Strength And Toughness Aluminum Alloy Parts

Squeeze casting is a advanced molding processing technology to deal with liquid meal which realizes the combination of forging and casting, it has advantages like good forming quality, high mechanical property and simple technology process . Squeeze casting has attracted a lot of attentions in the industrial community which has a strong technology advantage in the manufacturing process of high strength and toughness aluminum alloy .In this paper, the direct squeeze casting forming technology was researched on forming a bearing hook which is made from aluminum alloy ZL102. We have discussed the design and improment of the mold structure, optimization of process parameters, the causes and solutions of casting defects,and achieved good results.Based on the studies of predecessors, combining with the problems appearing in the experiments, the mold is modified. The samples were made by repetitive pouring tests. Though the microstructure analysis and the mechanical property tests of the samples, the technical parameters of direct squeeze casting when forming a bearing hook was found out, that is specific pressure 60MPa, pouring temperature 730~750℃, mold temperature 270~290℃and the pressure-holding time of the punch 10~15s. Under these technical parameters, the parts made have good surface finish, compact internal structures, small grain sizes and few casting defects. Through T4 heat treatment, the tensile stress of the parts can reach to 310MPa, the elongation can reach to 18.9% which is obviously better than the traditional casting by metal molds.The casting defects of the bearing hook during the squeeze casting experiments were also analyzed in this paper, which mainly include cold-lap, mold sticking, shrinkage porosity and cavity, thermal crack and macrosegregation. The prevention measures were given corresponding to their forming causes and factors. The results showed that, after taking some corresponding measures, the casting defects can be removed and the qualification rate has gone up greatly ,which satisfied the using requests.