Analyses And Technology Study On Automobile Dryer Valve Body Die Castings

Die casting is an advanced method to shape metal, which can continually produce masses of precise castings with complex shape, contour clear and uneven thickness. So it has wide application prospect in the areas of motorcycle, automobile and aerospace.Die castings of this research are the automobile dryer valve body castings produced by a die casting factory in Qu Zhou, Zhe Jiang Province. It is very difficult to produce the valve bodies on account of complex structure, a plurality of holes and grooves. With the existing technology conditions, when producing the valve bodies, here come out some phenomenon such as lots of shrinkage and blowhole, unqualified hermetic seal tests and low-quality die castings. Taking this valve body as an example, its starting point is to reduce the castings’ defects and improve the qualified rate of the products, then carry out the research of die casting, numerical simulation and experiment analysis of application and so on. The main work and conclusions are as follows:Firstly, the valve casting is analyzed in detail, the set of quality inspection process is analyzed, the defect types and position distributions are counted, the defect prone regions are determined, the mechanism of the formation of the defects is expounded, and a preliminary solution is put forward.Secondly, mold filling and solidification processes of castings are analyzed by establishing mathematical model of alloy filling and solidification process and using ProCAST software to do numerical simulation for valve body casting and a prediction is made that is the probable areas where the defects come out, finally, the results and the actual production basically tallies. Thirdly, according to the design principle of the gating-exhausting system and the actual casting defects, two schemes are put forward in order to optimize the design of the gating-exhausting system, based on the simulation results, the two schemes are compared and analyzed, and then the optimal scheme is obtained.Fourthly, on the basis of orthogonal testing method, a group of numerical simulation schemes are designed to analyze castings’ mold filling process, solidification process comprehensively and predict casting’ defects, then the best combination of process parameter is determined(6.2 meters per second,650℃ pouring temperature and 220℃ mold preheating temperature).Fifthly, die castings with less defects, accurate sizes meet the practical use, which can be gotten by modifying the gating-exhausting system structure and process parameters to do die casting tests.To sum up, based on the valve body die casting defects, mold structure and process parameters are optimized by using numerical simulation technology and the accuracy of the numerical simulation is testified, so the actual problems that occur during the valve body die casting production are solved, and the quality of products are improved, meanwhile, enterprises’economical, social profits are prompted.