抄録
In the present work, the heat transfer phenomena at the casting-resin-coated sand core interface and the structure of surface layer in casting have been studied using squeeze method with pressure of 0.230 and 820kgf/cm2. The heat transfer coefficient and the heat flux at casting-core interface were calculated by the heat balance equation. The surface structure of castings was examined with metallographic method.
The heat transfer coefficient at the casting-core interface increased with increasing force of applied pressure. The values of heat transfer coefficient at the interface under gravity, 230kgf/cm2 and 820kgf/cm2 are 0.0005, 0.0015 and 0.0017 cal/ (cm2·s·°C), respectively. The changes of heat transfer coefficient at the interface have been influenced on the condition of contact between castings and core. When the pressure is 0kgf/cm2, the surface of castings is rough. Smooth surface is found when the pressure is raised from 0 to 820kgf/cm2. In case of 0kgf/cm2, the structure of surface layer at the interface are coarse. On the other hand, the microstructure of castings at the interface is fine under pressure of 820kgf/cm2. Solidification rate in the castings is extremely rapid and therefore fine chill surface forms. The heat transfer coefficient at the castings-core interface corresponds well with the structure of surface layer of castings.
