Crankcase Permanent Mould Low Pressure Die Casting Numerical Simulasition And Casting Technology Research

With the development of auto industry, low pressure casting has attractedmore and more attention. However the research on low pressure casting in ourcountry starts late. And in the designing of low pressure casting process, lots offactories still use the criteria for gravity casting.That results in poor quality casting,and process produced low.In order to solve that problem, this paper studied thefilling flow and solidification feeding behavior of typical structure based onnumerical simulation, and applied the conclusion into the low pressure castingprocess design of crankcase. Through simulating the filling solidification andcycle casting process, optimized its casting process. The main results are asfollows:The temperature changes of AC4B during solidification in H13mould hasbeen measured though experiment. And then calculate the interface heat transfercoefficient between AC4B aluminum and metallicusinganti algorithm. Find thatthe interface heat transfer coefficient is a function of temperature. So the boundaryconditions fornumerical simulation are optimized.For the low pressure casting solidification feeding process, a mathematicalmodel isbuild. And based on the model, the linear relationship betweenfeedingpressure and criticalsolid fraction has been derived. Critical solid fraction affectsthe shrinkage in casting. When the critical solid fraction increases, shrinkagereduced, and when the criticalsolid fraction at the rate of0.6to0.8, shrinkagedecline obviously, when the critical solid fraction is greater than0.8, the criticalsolid fraction impacts little on shrinkage.Focused on the thick-walled castings often occur in the low pressure casting,design a simple model. By simulating thefilling process, discovered that the usingof modulo method in ingates modulus design, and making cross-sectional shape ofthe ingates close to the runner-sectional shape of the casting, can effectivelyimprove the smoothness of the filling. Comparing filling process of differentmodels filling speed,find that the smoothof free surface affected by the width ofthe jet zone inside flow.The crankcase casting ingatesare designed using modulo method, and bysimulation finding that with the filling speed of5cm/s, the filling process smooth.Though simulating its solidification process, determine the mold cooling solutions,and holding pressure was optimized.Analysis of the temperature changes of molds and castings under different process, determine the best mold cooling solution,based on cycle casting process simulation.Finally, in order to prove the simulation results, the paper makesactualcrankcase casting, and studies the microstructure and mechanical properties of theAC4B aluminumat different thickness location of the casting under permanentmould low pressure casting condition.