Effect Of Vibration Transmission On Shrinkage Defect Of High Strength Aluminum Alloy By The Low Pressure Casting

High strength casting alloy ZL205 A has the advantages of high strength,high toughness,low density and the low pressure casting has the advantages of easily control,closer casting structure,well performance and higher productivity,thus,it has been widely used in the aviation,aerospace,military and civilian industry.Actually,it still detect the casting defects,which even more badly than gravity casting defects in the low pressure casting.As a result,the vibration casting technology,using vibration transmission to affect the casting solidification process,in turn,reduce the shrinkage defects,increase the density of aluminum alloy castings.It has important theoretical significance and practical value to improving the technology of low pressure casting and the quality of casting.Based on the numerical simulation to determine the vibration transmission for the effect of casting solidification area,and the physical simulation experiments of the porous structure in the solidification area and of the melt flow in solidification area in the vibration transmission under the condition of low pressure was designed.By using the sand model of different size and different colors to simulate the solidification porous structure and microcrystalline wax to simulate the alloy material,it was learned that the effects of vibration transmission on the porous structure and the seepage under low pressure area.The results show that mechanical vibration has the best effect on the porous structure under the condition of low viscosity and high porosity,while it has little effect on the densification area.At a certain temperature,the mechanical vibration can effectively promote the seepage.In the experiment with temperature gradient,it is difficult to get the seepage flow in the low temperature area,only in the high temperature area cloud do it.So,for the structure is relatively loose,mechanical vibration is by changing the solidification structure to feeding,and in the area of higher density,the seepage feeding was conducted by the mechanical vibration.And applying vibration based on the above results in the process of low pressure casting,it can be seen that the mechanical vibration cloud affect the shrinkage defect.Under the vibration,shrinkage defects became smaller and the distribution concentrated.Therefore,mechanical vibration can influence the existence form,quantity and distribution of shrinkage cavity.In fact,the vibration force can promote the concentration of shrinkage cavity and porosity,and the vibration frequency can effectively change the number and size of shrinkage cavity and porosity.On the average density analysis of the orthogonal method,in the experiment,the optimal process parameters combination was 720?,7Hz,100 V,its density compared with other groups,was the largest which can be increased by 1.5%.The feeding technology of vibration transmission to improve high strength aluminum alloy in the low pressure casting was applied on the annular castings,the results show that under the vibration transmission,shrinkage defect of annular casting has a significant impact.It accorded with the law.Therefore,vibration transmission can improve the casting quality and reduce the casting defects.It is meaningful to apply vibration transmission in low-pressure casting.