| In the production of castings,the reasonability of casting technology is the most important factor to determine the quality,cost,production and development cycle of castings.Filling mold and cooling solidification are two important steps in the casting process.Filling mold is a mechanical process of changing movement speed,while cooling solidification is a process of heat transfer leading to crystallization and microstructure change.The key to obtain high quality castings is to control the quality of the molding process.The rationality of the casting process is often the most important factor to determine the quality of the castings and the duration of the project.Focusing on the water pump of a certain automobile engine cooling system,this paper mainly studies the sand casting process of the water pump housing(the housing size is about 240×200×150 mm,the single weight is 5.4 KG,the annual order is about 20,000 pieces).Analysis foundry technology theory,models by Pro/E and use casting simulation software procast to simulate the filling and solidification process to analyze the deficiency of the existing casting process and to raise solutions.The results show that:1.The position of the central hole of the pump castings,because it is close to the inner gate,change riser from 40 mm in diameter,65 mm in height to 50 mm in diameter and 80 mm in height,can make the final solidification position been compensated effectively,so as to realize the whole sequential solidification and eliminate the shrinkage defect of the central hole of the castings.2.The isolated liquid phase area in the foundation bed of the pump housing,through the triangular chill with the length of 65 mm,40 mm and 55 mm and the thickness of 32 mm can achieve partial simultaneous solidification.In this experiment,by applying cooling coating on sand core.The test results show that the shrinkage defect in the central hole and foundation bed of castings was effectively improved from 20% to 1%. |
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