Fig. 1 to Fig. 3 are isochronous graphs of liquid metal filling pattern of lost foam casting under different pouring modes of flat plate model. When the bottom pouring pouring system is adopted, the filling shape of liquid metal in lost foam casting is similar to that of cavity casting. It is filled layer by layer from the bottom to the top. The front of liquid metal is convex, the isochronous curve of liquid metal filling is dense, and the filling speed of lost foam casting is slow, about 1 / 30 of that of cavity casting.
When the middle pouring pouring system is adopted, the liquid metal in lost foam casting does not reach the bottom of the mold first and then fill up. Instead, it is filled forward from the inner gate in turn. The shape of the front edge of the liquid metal is not regular radial arc. The isochronous curve below the center line of the inner gate is large and the isochronous curve is sparse. The filling speed of the liquid metal is fast, and the isochronous curve above the center line of the inner gate is small, The isochronous curve is dense and the filling speed of molten metal is slow. The last filling position of molten metal in lost foam casting is the farthest from the upper part of the model to the ingate. This is because the gravity of molten metal changes the filling driving force of different parts with the filling process. The filling driving force above the center line of the ingate becomes smaller and the lower filling driving force becomes larger. When the side is introduced into the ingate, the metal liquid advances forward in a radial arc shape. At the initial stage of filling, the isochronous curve is sparse, and the metal liquid filling speed is fast. With the filling process, the isochronous curve becomes dense, and the metal liquid filling speed of lost foam casting reaches a relatively constant value.
In the side injection mode, at the initial stage of lost foam casting metal liquid filling, the degree of superheat of the metal liquid is high, the viscosity is low, the pattern gasification and decomposition speed is fast, and the static head of the metal liquid does not change with the filling process. Therefore, at the initial stage of filling, the metal liquid has a relatively fast filling speed, and the pattern gasification and decomposition disappear to absorb heat. The metal liquid of lost foam casting is cooled and the degree of superheat is reduced, The fluidity becomes poor and the filling speed becomes slow.