How to avoid aluminum die casting mold defects ?

Main reasons for cracking of aluminum alloy die casting mold:

1. During die casting production, the temperature of aluminum material is high.

2. Mold release agent spraying is unreasonable during die casting production.

3. The heat treatment of the mold is not ideal, and the hardness shall not be less than hrc-37

4. It is recommended to use 8407 or refined H13 or higher materials due to improper material selection (or poor quality of mold steel).

5. The cooling system or water transportation operation of the mold design is not good.
 

In general, the early cracking is due to the high starting forging temperature of the blank forging (known as overburning). Overburning is an irreparable defect. Therefore, the starting forging temperature in the blank manufacturing process should be strictly controlled, as well as the quenching process, and the heating time should be strictly controlled to prevent decarburization.

After the material is selected, the heat treatment is completed. After a certain amount of material is produced, the stress shall be removed. In addition, the design shall be reasonable to avoid stress concentration as much as possible, and the size of R angle shall be controlled.

At about 10000 times, the mold should pay attention to tempering and stress relief. The residual hard force of internal force concentration processing has not been removed, and the thermal stress of die casting process has not been well removed. In short, cracking is the manifestation of stress concentration. Multiple tempering can be used to remove the stress to increase the mold life.

The main reasons for cracking of aluminum alloy die casting mold after a period of production are as follows:

1. The mold temperature is too high and the stress is too large.

2. The mold core material does not use high-quality materials.

3. Mold heat treatment hardness is too high or too low.