This Research is focused on deciding the optimal casting conditions in DC casting (Direct Chill Casting) process. To produce 7-inch diameter 7075 Al alloy ingot, the casting speed, the amount of cooling water, the pouring temperature and the melt height in mold are chosen for factors which have 3 levels each.
Using $L_{27}$ OA(Orthogonal Array), only some parts of all the cases are performed to reduce time-consuming effort.
The best ingot is considered to be the one with the finest microstructure. To quantify the measure of the size of microstructure, DAS(Decdrite Arm Spacing) is used. The data of each case are analyzed by ANOVA(Analysis of Variance).
The amount of cooling water and all 3 interaction efforts considered do not have significant effect on the fine microstructure. And under the condition of higher casting speed, higher pouring temperature, and lower melt height in mold the ingot with best quality can be produced.
