The filling time of turbine exhaust pipe in lost foam casting is longer than that in sand casting. The whole filling process can be observed through the viewcast window, as shown in Figure 1. Figures a ~ d once show the state diagram when step = 940, step = 1960, step = 3920 and step = 4740 in the filling process:
From the simulation results and analysis, it can be seen that the liquid metal mainly has the following characteristics in the filling process of turbine rear exhaust pipe:
(1) By observing the filling sequence of liquid metal in the mold cavity according to time, it can be seen that the liquid metal filling in lost foam casting is faster at the part close to the sprue, and the liquid metal filling is slower at the part relatively far away from the sprue.
(2) As the exhaust pipe after the turbine is a small thin-walled part, its filling form is different from the general filling order from the whole step pouring process. Specifically, on the whole, the liquid metal is filled in sequence, but the filling starts basically at the same time on the two inner sprues of lost foam castings. As the filling continues, the filling of liquid metal gradually tends to be stable.