Magnesium Alloy Lost Foam Casting Filling Performance Numerical Simulation

Magnesium alloy has been applied widely in the space of aerospace, automobile and tele-communication industries for its many advantages. Currently, as an important casting production process for magnesium alloy, the lost foam casting (LFC) also needs to be improved. The LFC regarded as a costing-effective and environment-friendly casting process. The LFC for magnesium alloys is a new technology combines the advanced materials and advanced production process, and has great advantages in the production of complex cavity and thin-walled. The combination of the magnesium alloys with LFC will bring a bright future for magnesium applications, especially in forming components with complex-geometry and thin-wall. The liquid metal filling ability of the lost foam casting process is different from the cavity casting very much, due to the interaction between the pyrolysis of the foam pattern and the liquid metal. The rule of filling in casting can be qualitative semi-quantitative researched and predicted. In this paper, the filling capacity of LFC was researched by using different models.In this paper, many technological factors of the lost foam casting were selected. The impact of pouring temperature, negative pressure and pouring head on the fluidity was carried out by using orthogonal test. The result shows that pouring temperature was the most effective parameter to improve the fluidity. The fluidity of magnesium alloy increased with pouring temperature. Impact of the negative pressure on the casting length was nonlinear. The largest length appeared in the case of 0.3atm negative pressure; however, the flow length would decrease along with the continued increase of the negative pressure. The flow length would decrease with increasing head which impact was minimal.A form model was designed to research the multi-directional flow and defects in the complex cavity of magnesium alloys lost foam casting. In the model, compared with the traditional cavity casting, mold filling of LFC was more smoothly and the eddy current was less. Slag inclusion may be from the intersection of the liquid metal. Thermocouples were embedded in foam pattern to record the flow of molten metal and temperature variation in experiment. Experimental results were basically consistent with the simulation's.A vertical plate model was designed to study the sensitivity of gravity in LFC. The guiding role of gravity was completely offseted in mold filling because of the existence of the foam pattern. It reduced the molten metal erosion and rolled phenomenon in the normal casting.