The cause and solution of crack in casting aluminum alloy

Casting aluminum alloy Aluminum alloy, aluminum alloy castings can be obtained directly from parts by the metal casting process. The alloying element content of these alloys is generally higher than that of the corresponding deformed aluminum alloys.

The content of alloyed element silicon in cast aluminum alloy is larger than that in most deformed aluminum alloys. In addition to the reinforcement element, the cast aluminum alloy must contain a sufficient amount of eutectic element (usually silicon) so that the alloy has considerable fluidity and is easy to fill the shrinkage joint of the casting.

Casting crack is a crack formed at a higher temperature in the volume shrinkage of large alloy and more complex shape of the casting prone to appear.

Cause:

1. The structure design of castings is not reasonable, with sharp corners and the wall thickness changes are too different

2. Sand mold (core) is not conciliatory

3. Local overheating of the casting mold

4. The pouring temperature is too high

5. Premature removal of castings from the casting mold

6. Heat treatment overheating or overburning, cooling speed is excessive

Solution:

1. Improve the structural design of castings, avoid sharp corners, and strive for uniform wall thickness and smooth transition

2. Take measures to increase the yield of sand mold (core)

3. Ensure that all parts of the casting are solidified simultaneously or sequentially, and improve the design of the pouring system

4. Properly reduce pouring temperature

5. Control the cold drawing time of the mold

6. Hot calibration is adopted when casting is deformed

7. Correctly control the heat treatment temperature to reduce the quenching cooling speed