(1) The refractory powder in the coating is much finer than the particles in the mold (core) sand. After brushing the coating, it closes the pores on the surface of the mold (core), preventing the metal liquid from penetrating into the surface layer of the mold (core), and avoiding the defect of mechanical sand sticking in the cast iron platform casting.
(2) The various refractory fillers in the coating have good thermal conductivity, large heat storage capacity, and high refractoriness. They can reduce the contact time between the liquid metal and the mold, causing the liquid metal to stop flowing prematurely, thus reducing the depth of liquid metal penetration into the mold pores and preventing mechanical sand sticking in the casting.
(3) According to the theory of easily strippable sintered sand layer, in view of the production characteristics of different cast iron platform castings, appropriate refractory powders and fluxes are selected in the preparation of coatings, and an appropriate combination of multiple refractory materials is adopted to lower the sintering point of refractory aggregates. This achieves a situation where during the pouring of molten metal, the coating easily sinters, forming a stable glassy isolation layer, which helps prevent sand sticking. Moreover, during the cooling process of the casting, due to the difference in contraction between the casting and the sintered layer, the sintered layer automatically peels off.