Before casting, preheat the mold to a certain temperature TMI, and the casting temperature of liquid metal is TP; when the liquid metal is poured into the mold and contacts with the inner wall of the mold, a very thin layer of casting mold interface is formed instantly, and the initial temperature of casting mold interface is T1, that is:
Because the latent heat of solidification is not considered in this paper, the value of T1 is calculated according to the following formula
Where, ρ Mo and ρ CA are the density of mold and pipe material respectively, and CMO and CCA are the specific heat capacity of mold and pipe material respectively.