On the production of a356 aluminum alloy brake-oil pump housings by the evaporative pattern casting process

摘要

The aim of this research is to establish the optimal processing parameters which are required for manufacturing sound EPC A356 brake-oil-pump housings. The processing parameters studied include the gating system design, the pattern material, the coating thickness, the GFN of molding sand the application of a vacuum and the pouring temperature. The optimal conditions have been respectively established for various gating systems ranging from one layer-one casting system (Type A) to low-layer-six casting system (Type D). The mold filling behavior of the gating system Type D has been thoroughly analyzed, with the results indicating that though the metal flow follows essentially a sequential pattern, the majority of the first incoming melt (approximately 70%) enters the lower layer. This is due primarily to the relatively large metallostatic head and the cross sectional area of the sprue used in this study. In addition, the previously derived EPC Al flow-solidification equation has been slightly modified to calculate theoretically the flow length of pipe-shape castings, similar to the pump housing casting studied herein. The calculated flow lengths are in good agreement with the experimental results.