A continuous casting process with a porous mold was studied. Nitrogen gas flows through the porous mold to prevent contact between the melt surface and the mold. The porous mold was made by hot pressing of Cu powder, and the melt was Sn.
Before the continuous casting, the melt was solidified in the porous mold with gas flow in static condition to observe the interface between the mold and the liquid. A numerical simulation program was made to predict the shape of the solidified shell and the effect of operating variables. The results of experiment with and without porous mold were compared. The casting speed was 3 mm/sec and the frequency of the mold oscillation was 1 Hz. The casting was a round bar of 40 mm diameter. The melt was removed during the process to observe the real shape of the solidified shell. The macrostructure of the casting was examined.
The heat transfer rate to the mold was decreased by the gap caused by the gas flow. The fraction of the equiaxed grain increased. The contribution of the heat extraction by the gas flow was negligible.
