Results and discussion For centrifugal casting the movement of liquid is determined by the resultant force which is caused by different mold rotation speeds. The flow pattern changes according to the changing of rotation speed. The velocity loss rate of liquid has no significant change.
Effects of rotation speed on flow pattern In horizontal centrifugal casting, the liquid follows a circular motion due to the rotation of the mold in radial direction. In axial direction, it fills the mold as thread. With the action of resultant force, the liquid sticks to the wall of the mold to fill which is never happened in gravity casting. It can be seen from Fig. 3 that the flow pattern is quite different between group one and group seven.
In Fig the flow pattern acts as thread and in Fig.it acts as strip. In Fig. the rotation speed is the lowest—only 305rpm. In Fig. the rotation speed is the highest—600rpm. This is because the higher rotation speed the higher pressure it will lead to the liquid, and it will cause the liquid film thinner and wider. This means that as the rotation speed increases, the liquid fills the mold more uniformly. The rotation speed plays an important roll in the flow pattern of the liquid in horizontal centrifugal casting.
It can be concluded that in horizontal centrifugal casting the liquid forms a
thin film in the mold at first. This thin film solidifies quickly in real
casting process because of the low temperature of the mold. The quick
solidification of the thin film makes the grain refined. Consequently, it is
beneficial to change the initial temperature of the mold and control rotation
speed to gain refined grain