| Hypoeutectic Al-9%Si and Al-4.5%Cu alloys were casted in four kinds of ingot case materials with different thermal conductivity, and the solidification phenomenon was investigated by measuring shrinkage cavity, centerline feeding resistance, cooling rate of melt, temperature gradient of ingot cases and interdendritic arm spacings. The ingot case materials studied were flake graphite cast iron(FGCI), CV graphite cast iron(CVGCI), spheroidal graphite cast iron(SGCI) and FGCI/CVGCI/SGCI from the bottom side of an in got case. An ingot case composed of FGC/CVGCI/SGCI showed less shrinkage cavity and centerline feeding resistance than those of either FGCI, or CVGCI or SGCI. The cooling rate of melt was a bout 1.5℃/sec faster at the sideline than at the centerline of the melt. The secondary dendritic arm spacing was measured to be inversely proportional to the cooling rate of the melt. |
|
