Effect of process parameters on Si segregation in an aluminum alloy during squeeze casting

The effects of pouring temperature, squeeze pressure, squeeze speed and cooling type on Si segregation in 6066 alloy were studied in indirect squeeze casting. Taking the difference between the silicon content of the hot spot zone after solidification and the initial silicon content of the alloy as the segregation degree, the Si segregation was analyzed according to orthogonal design which considers two levels, four factors and partial first-class interactions. The results show that pouring temperature, squeeze pressure, squeeze speed and cooling type all have effect on the Si segregation, but pouring temperature is the most significant factor. With the increase of pouring temperature, the segregation degree of Si decreases. Squeeze pressure and squeeze speed have less influence on the Si segregation than pouring temperature, but their influence trends are opposite. The influence degree of mold cooling is similar to that of the partial first class interaction of squeeze pressure and speed. The Si segregation in a copper sleeve (high cooling speed) is lighter than that in a steel sleeve (low cooling speed). Negative Si segregation was found in the hot spot zone of indirect squeeze cast work-pieces.