Common problems in aluminum casting

Common problems in aluminum casting are: pores, cracks, shrinkage cavities, shrinkage, and cold separation.

Porosity: The porosity defects of cast aluminum parts can be divided into five types: intrusion pores, wrapped pores, precipitated pores, endogenous reaction pores, and exogenous reaction pores. The longest seen in aluminum castings are the first three types of porosity defects.

crack:

There are two main reasons for the cracking of aluminum casting parts: the solidification mode of aluminum castings and the casting stress during solidification. Aluminum castings have a wide range of solidification temperatures. Shrinkage and shrinkage are manifested by the rough surface of the hole wall and the irregular shape, which usually occurs at the final solidification of the casting and at the hot section. The shrinkage is in the late stage of solidification, and the liquid phase in the solidification zone is divided into a single small molten pool by the dendrite, and the small molten pool cannot be compensated for by the volume shrinkage during solidification. Alloys with a wide range of crystallization temperatures are most likely to form shrinkage. Cold partition

The cold partition presents a crack-like gap, but the slit has rounded edges. Most of the cold barrier defects are formed by the solidification blockage of the flow head. The solution to the cold insulation defect is mainly to improve the filling ability of the molten metal, including increasing the pouring temperature, increasing the mold temperature, improving the exhaust gas, and optimizing the design of the pouring system.