Why are all 6063 aluminum alloy bars loose, but 1070 pure aluminum is not? Use a hot top casting system.

6063 aluminum alloy belongs to aluminum magnesium silicon alloy. Although the alloy content is small, there is also a solidification interval, which is estimated to be between 20℃ and 30℃ according to the phase diagram. If the cooling speed of the external mold is slow and the continuous casting descends quickly, there must be axial shrinkage cavity. Pure aluminum has only one freezing point, and there is basically no shrinkage cavity.