The centrifugal radius of complex and small castings presents minuscule in centrifugal casting

which can often result in small centrifugal force to fill inadequately The mechanical properties of ZTC4 Ti alloy castings by rapid investment casting with vacuum gravity pouring were analyzed on the basis of optimizing the gating system.The results reveal that Polystyrene（PS）wax pattern with roughness less than 3.2μm prepared by selective laser sintering（SLS）technology can shorten greatly the development cycle.Gravity pouring impeller with vacuum degree of 4 Pa has a surface roughness less than 6.3μm

and X-ray detection presents defect free.The yield strength

tensile strength and elongation of the samples reach 805.67 MPa

922.67 MPa and 12.03%

respectively.The metallographic observation indicates that the homogeneous Widmanstatten structure is distributed in the alloy

meeting high-grade casting conforming to GB/T6614-2014 standard.