Numerical Simulation And Processing Optimization Of Four-circuit Protection Valve Die-casting

Die casting is commonly used in automotive industrial and aerospace,which has high forming accuracy,excellent surface quality.But the actual production of aluminum alloy in die casting often forms cold separation,cracks,pores and impurities,etc.,which greatly reduces the airtightness and strength of the casting.Traditional die-casting processing optimization used trial-and-error method.Numerical simulation technology can simulate the actual production and optimize process flow,not only cuts costs but also reduces defects.In this dissertation researched on a four-circuit protection valve.The whole processing of die-casting production was optimized by the combination of computer simulation technology and die-casting processing,to improve the quality of products.The main contents in this dissertation are as follows:(1)Through the investigation the reject rate of the valve was 24%.Analyzed the main reasons for the defects of die casting,the corresponding measures was put forward.(2)Based on ProCAST,two kinds of gating-feeder were designed.Through the simulation of the temperature field of casting,the location of the hot section,the size of shrinkage and porosity of the castings,the placement of the gating-feeder of casting was determined.(3)Comparing the optimized system's gating-exhausting system with the original system,the source of defect was found.Based on ProCAST,through the numerical simulation of velocity field,temperature field,stress field and internal defects,the optimum processing parameters were determined.The injection speed was 4.0m/s,the pouring temperature was 650?,and the preheating temperature was 220?.(4)According to the die casting tensile experiment,the microstructure and cutting observation of the new and origin,the improvement of mechanical property,surface quality and internal pores were verified.In this dissertation,based on the numerical simulation technology,the optimal die casting process was determined.Based on ProCAST,the casting yield increased from 76% to 95%,and the economic and social benefits of enterprise were improved.