Inlet Condition for Mold Filling Simulation in Gravity Casting of Aluminum Alloy

Abstract

The casting CAE is useful tool for casting design in order to obtain the sound castings without defects. It is very important to know the influence of casting conditions on the mold filling. In the present study, the inlet condition for the mold filling simulation in gravity casting of aluminum alloy is investigated to simulate the real phenomena changing with the difference in the casting shape. The direct observation experiment is carried out with six types of sprue designs using an aluminum alloy and sand mold. There are three types of sprues: the elbow, bend and stair-step shapes. The molten metal of Al–7%Si alloy is poured using the stopper ladle. The velocity change in accordance with the different casting condition is analyzed using images observed by the video camera. The velocity of flow front in the early stage of the mold filling is changed intensely. Then, the velocity after the middle stage of the mold filling is decreased calmly. It is difficult to simulate the present phenomena by the mold filling simulation using the velocity inlet boundary. In order to reproduce the difference of each filling behavior, new inlet condition, which is named to “OverFlow pouring Basin” (OFB), is proposed in this study. The mold filling behavior and filled-up time simulated using the inlet condition of OFB are more or less agreed with six real phenomena according with three sprue shapes and two sprue heights.