消失模铸造中泡沫热解气体逸出的数值分析

Numerical Analysis of Foam Degradation and Gas Diffusion in Lost Foam Casting Process

消失模铸造中受泡沫模样热解气化的影响,使得消失模铸造成形过程比普通砂型铸造复杂得多。基于ProCAST的计算流体动力学求解内核,研究了球墨铸铁QT250消失模铸造时泡沫遇高温金属液发生热解,在金属液与泡沫间产生气隙,气隙气体从型砂中逸出的速度、压力大小及其分布的相关规律,以及对铸件成形质量的影响。为实际生产提供有益参考。

With the influence of foam degradation and gas diffusion during mould filling, the lost foam casting （LFC） process, compared to the common casting process, is much more complicated. In this study, based on the computational fluid dynamics （CFD） model of the commercial code ProCAST, the rules have been researched such as the melting, vaporization and degradation of the foam pattern when it meets the molten metal front, the forming of the kinetic zone between the melt and the receding foam pattern, the flow velocity and pressure contour of the gas overflow from the molding sand, as well as their influence on quality of the QT250 ductile iron castings produced by LFC. The results offer a useful reference for the practical production.