Remarks to the hydraulic centrifugal casting pipes

The shapes of inner melt free surface while centrifugal tube casting are considered. The Froude number for centrifugal force field is introduced to predict the shapes of the free surface during a solidification. Stable coaxial cylindrical surface of melt for the case of thin wall tube is stated. It is shown that to the end of solidification the inner free surface has no excentricitet anyway.