| Aluminum alloy high pressure die-castings are widely used in various industrial fields for their high dimensional accuracy, good surface quality, high material utilization, good economic returns,etc. The determination of process parameters depends on the production experience of many years in traditional high pressure die-casting production, the accuracy is very low. Numerical simulation technology is a good guide to the actual production.The numerical simulation of flow field and temperature field can predict the location and size of the defects before the casting. It can optimize and determine the optimal process parameters, and reduce the high pressure die-casting defects, avoiding the human and material resources waste. High pessure die-casting production is moving to the road on which is directed by scientific theory from by experience.Casting shell is a main part of the gas meter, considerable difficulties appear in high pressure die-casting because of its complex structure, the thin wall and so on. The yield of the shell is very low now, shrinkage is the major defect, which leads to pressure test failure. It greatly reduces the productivity of the casting.The main research content in this paper is divided into the following, they include modeling for the shell, meshing, determination of the boundary conditions and initial conditions, analysis of filling, solidification and shrinkage number of each group parameters. It can optimize the high pressure die-casting process parameters, reduce the amount of shrinkage, improve casting yield.The optimal high pressure die-casting process parameters are obtained through simulation using ProCAST software, pouring temperature 630℃, mold preheating temperature 190℃, injection speed of 3.5m/s, pressure 70MPa, inside gate thickness of 2mm. Based on the above parameters, the liquid alloy filling smoothly, the number of shrinkage is least. It meet the requirements of high pressure die-casting for porosity.It is validated by the experiment that the filling time, solidification time agree with the actual production for these parameters. The casting pass rate is more than 95%, the problem of more shrinkage is well solved for the company for the shell casting. The optimum die-casting process parameters determined through numerical simulation have been applied to the actual production. |
