Pouring the molten aluminum: This stage involves carefully pouring the molten aluminum into the prepared aluminum alloy sand casting parts cavity. Here's a detailed explanation of this critical step:

a) Furnace preparation: The first step involves preparing the furnace for melting the aluminum alloy. The furnace, typically a crucible or electric induction furnace, is heated to a precise temperature suitable for melting the specific aluminum alloy being used. This temperature is determined by the alloy's melting point.

b) Skimming and degassing: Before pouring the molten aluminum, it is important to skim off any impurities or dross that may have formed on the surface. This ensures a cleaner and higher-quality cast. Additionally, degassing processes may be employed to remove any dissolved gases that could lead to defects in the final casting.

c) Ladle pouring: Once the aluminum is properly melted and prepared, it is transferred into a ladle for controlled pouring. The ladle acts as a container to hold the molten aluminum and allows for precision control during the pouring process.

d) Pouring technique: The molten aluminum is poured into the mold using a controlled and consistent technique. It may involve tilting the ladle or using a pouring basin or runner system to direct the flow of the molten metal. Care must be taken to ensure that the aluminum fills the mold cavity completely, without causing turbulence or air entrapment.

e) Solidification: After the molten aluminum is poured, it begins to solidify rapidly inside the mold cavity. The cooling rate can significantly impact the casting's microstructure and mechanical properties. Proper control of cooling and solidification is essential to achieve the desired characteristics in the finished casting.

f) Risers and vents: To compensate for the shrinkage that occurs during solidification, risers or feeders are often added to the mold design. These reservoirs are connected to the mold cavity and provide additional molten metal to compensate for the shrinkage and prevent defects such as shrinkage porosity. Vents are also included to allow escape of any trapped air or gases during the pouring and solidification process.

g) Cooling and removal: Once the casting has solidified, it is left to cool within the mold. The cooling time varies depending on the size and complexity of the casting, as well as the alloy being used. After sufficient cooling, the mold is opened, and the casting is removed. Any excess sand or gating system attached to the casting is carefully removed through methods such as vibration, shot blasting, or machining.

The pouring process requires precision and careful control to ensure a successful aluminum alloy sand casting. With proper execution, this step enables the transformation of molten aluminum into a solid, intricately shaped part with the desired mechanical properties.