Centrifugal investment casting of large thin-wall titanium alloy cylinders (with diameter of 660 mm,
height of 750 mm and thickness of 4 mm) has been studied. The results show that small centrifugal force (or low rotation
speed) leads to incomplete fill of the cylinder mould by Ti-6Al-4V melt, while complete fill of the mould cavity is
achieved at large centrifugal force. For properly filled cylinders, the quantity of internal pores decreases with increasing
centrifugal force. For a given rotation speed and shell mould with uniform temperature field, the density of porocity
increases with the length of melt path. By using shell moulds with an yttria face coat, precision cast parts with high
surface quality free of α case can be obtained, and the internal porosity can be eliminated by HIPing. Grain size of the
castings tends to vary significantly with cross-section thickness, and needs to be adjusted through measures such as
post-casting heat treatment and composition modification.