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本文通过测量温度和金属与铸型间的间隙来研究凝固过程中金属与铸型界面传热行为及气隙形成规律。实验表明:由凝固过程中金属和铸型产生的收缩或膨胀是产生界面气隙的主要原因。在凝固初期,气隙的形成主要是铸型受热膨胀向外移动所致,而随后铸件凝固产生的收缩造成了金属与铸型间气隙的扩大。气除形成后,界面传热由固体接触导热转为气体导热和辐射传热。界面换热系数约为气体导热系数和辐射传热系数之和。
In this paper, the temperature and the gap between the metal and the mold were investigated to study the heat transfer behavior and the air gap formation between the metal and the mold during the solidification process. Experiments show that the shrinkage or expansion caused by the metal and mold during the solidification process is the main reason for the interface air gap. In the initial stage of solidification, the formation of the air gap is mainly caused by outward expansion of the mold due to thermal expansion, and then the shrinkage of the solidification of the casting causes the expansion of the air gap between the metal and the mold. After the formation of gas, the interface heat transfer from the solid contact heat transfer to gas heat and radiation heat transfer. The interface heat transfer coefficient is approximately the sum of the gas thermal conductivity and the radiative heat transfer coefficient.