Study On Composite Process Of Sand Casting And Lost Foam Casting For Complex Shaped Casting

Traditional sand casting is the most widely used in the current number of foundryenterprises in China. As a new method of casting, the lost foam casting (LFC) is adoptedby more foundry enterprises for its distinct advantages. Sand casting and lost foam castingeach have distinctive technological features, as well as the existence of their ownshortcomings. So the key of this paper is to combine the sand casting with LFC processwhich can develop its advantages and avoid its disadvantages. The application on the twotypical castings, the cast steel joint for construction and the impeller of desulfurizationpump, was studied by using the composite process in this paper.The three-dimensional model of the cast steel joints is designed by using UG softwarebased on the architectural drawings. The static analysis of cast steel joint is accomplishedby using Finite element program. It is found that the structure of intersection joint wasvery irrational. There is a serious case of stress concentration on the interface of the pipewhich was seriously affecting the performance of the cast steel joint. After detailed designby adding rounded corners and the filled region, the bearing ability is greatly improved.The composite process of sand casting and LFC for the production of cast steel joints waspresented and the skills of the foam production are studied. Finally, the gating system wasoptimized by using InterCast software and qualified cast steel joints are producedsuccessfully. It is not only to resolve the difficult problems in molding process of complexspatial structure joint based on the high flexible design of LFC, but also to avoid thecarbon defects in the surface by using the composite process. The casting cost is reducedand the efficiency is promoted.The composite process of sand casting and LFC is presented for the impeller ofdesulfurization pump casting production according to the defects of the original process.The defect of the original process is that the whole sand core could not be acquired. So itleads to the low precision castings, high labor intensity of workers, as well as longproduction cycle and so on. The whole sand corebox and LFC foam mold of leaf weredesigned and manufactured for new composite process. The balance of the casting whichwas produced by adoption of new technology has greatly improved.