Direct research on different aluminum alloysAluminum alloy improves production processes, deepens our understanding of the phenomena that occur in these alloys. One phenomenon that occurs during the directional solidificationDirectional solidification of alloys is the columnar-to-equiaxed grain transition, known as the CETColumnar-to-Equiaxed Transition (CET) transition. In the present study, Al-Si alloys were directionally solidified, and an exponential relationship was found between the CETColumnar-to-Equiaxed Transition (CET) position and the cooling rate. Higher cooling rate values also caused the CETColumnar-to-Equiaxed Transition (CET) to run upwards from the samples. Regarding the silicon content, it was found to affect the CETColumnar-to-Equiaxed Transition (CET) position less than the cooling rate. At low and similar velocitiesVelocity, an increase in silicon content caused the CETColumnar-to-Equiaxed Transition (CET) to move to lower positions of the sample. In contrast, at higher velocitiesVelocity, an increase in silicon content did not significantly shift the CETColumnar-to-Equiaxed Transition (CET) position. At the eutecticEutectic concentration, the CETColumnar-to-Equiaxed Transition (CET) behavior did not resemble that of hypoeutectic compositions.