The solution of the heat transfer coefficient and the research method of the heat transfer behavior of the interface between the casting and the mold are derived from the metal mold and sand mold casting process, so it is necessary to summarize the research on the heat transfer behavior of the interface in the metal mold and sand mold casting process.
Sully et al. And Tillman et al. Carried out early research on the interface heat transfer behavior in the process of metal mold casting. They carried out experiments on castings and molds of different materials, and found that the heat transfer coefficient of the casting mold interface is a parameter that changes with time. After that, Ho and pehlke carried out a more systematic study. They used pure aluminum as casting material to study the variation of heat transfer coefficient of casting die interface with time under the condition of copper mold. Through their research, it is found that the heat transfer coefficient of the casting die interface changes with time, and the change rule of the heat transfer coefficient of the casting die interface calculated by the inverse algorithm is similar to that calculated by assuming that the gap layer is the air layer.
In addition, other researchers have also carried out relevant research. The research shows that the heat transfer between casting and mold during solidification can be divided into the following three stages
(1) After mold filling, the liquid metal keeps close contact with the mold, and the interface heat transfer coefficient increases rapidly to a large value.
(2) Under the chilling of the mold, the surface metal of the casting solidifies rapidly. Due to the shrinkage of the metal and the expansion of the mold, there are voids on the interface between the casting and the mold, but the contact between the casting and the mold can still maintain a good state, so the heat transfer coefficient of the casting mold interface can still maintain a relatively high value at this time.
(3) At the later stage of solidification, an obvious shell is formed on the surface of the casting. With the progress of solidification, the shrinkage of the casting and the expansion of the mold make an obvious gap between them. At this time, the heat transfer coefficient of the casting mold interface decreases rapidly to a lower level.