Finite Element Numerical Simulation Of Disk Casting Under Low-Pressure Die Casting

The filling process of metal liquid is the most important stage during the casting forming. Many defects, such as blow hole, slag, misrun, cold shuts and so on, occur in the course of filling, which can be attributed to unreasonable technological design. At the same time, The filling process of metal liquid can also affect on the solidification of metal liquid. Therefore, it is very important for high quality casting to understand and control the filling process of metal liquid.In the present paper, large-scale finite element analysis software ANSYS was used to analyse the flow field and temperature field of metal liquid filling and solidification under low-pressure die casting. The boundary and initial condition was located reasonably and some problem, such as phase transformation, turbulent flow and so on, was treated suitably. Based on the negativeof "mold filling instant" assumption, the flow field and temperature field in the filling process of disk casting under low-pressure die casting was couple-calculated. The above-mentioned successful simulation of disk casting can provide some reference to that of similar casting. The main conclusions are presented as follows.1. The results of orthogonal simulation indicate the factors which affect the fillingcapability are filling velocity, pouring temperature and die temperature in turn. By the simulation certificating, the adaptive pouring temperature of disk casting is 700℃, die temperature 310℃, and mold filling velocity 0.04m/s.2. For disk casting, the average velocity at the gate of rise-liquid pipe can be expressed as lgv_充=187. 4-39.2411gV-36.311gδ+10.391gh+31.681gT_浇+7.34T_模, which was deduced according to the normal simulation results. The above-mentioned expression can be used to guide the d filling process of low-pressure aluminium alloy disk casting with simple shape.3. The results of flow field simulation indicate that the filling velocity should be minished to avoid the defect formation, for the casting with small wall thickness, and a right angle at the corner shouldn't be adopted for avoiding empty.4. When the different heat transfer coefficients were used to simulate the flow field and temperature field, the change tendency of temperature field is uniform on the whole, but heat convection influences obviously the temperature of metal liquid in the mould during casting filling process. Higher the heat transfer coefficient is, lower the temperature of metal liquid in the mould by the end of the filling process.5. The relation between the temperature and the time during the casting solidification was measured using the thermocouple, and the measure result is accordant to that of numerical simulation, which proves our simulation work to be successful. Due to various factors, someerrors between tests and simulations are inevitable.