Effect of casting pressure on the castability of commercially pure titanium using a one-chamber casting machine

The purpose of this study was to investigate the effect of casting pressure on the combination of magnesia-based investment mold and one-chamber casting equipment (Symbion) for the castability of commercially pure titanium (CP Ti) and to compare the castability from this combination system with that of the centrifugal casting equipment (Selecast system). The castability of the mesh type specimen (n = 9) was evaluated in terms of the number of cast segments (castability index). The castability index was calculated as a percentage of the porous area for each mesh specimen versus the total number of complete cast segments. Kruskal-Wallis non-parametric analysis was conducted, and the castability indices of the three groups were compared using Dunn's multiple comparison test (alpha = 0.05). The Symbion 0.13 MPa group exhibited a significantly lower castability index than the Symbion 0.20 MPa and the Selecast groups. It was concluded that when the one-chamber casting machine is used with the magnesia-based mold material and 0.2 MPa gas pressure, the CP Ti castability index could be similar to that of the Selecast system.