铜合金低压铸造中浇不足缺陷的数值模拟

Numerical Simulation of Misrun during Low-pressure Casting of Copper Alloy

浇不足是铜合金低压铸造中常见的缺陷之一,采用数值模拟不仅可以预测铸件最终的浇不足形态,还可以进一步分析浇不足的产生与演化过程,而预测浇不足的关键是处理好合金糊状区对金属液流动的影响。针对铜合金修正了糊状区的变粘度-多孔介质-临界固相率模型,基于变物性参数计算并对比分析了其与变粘度-临界固相率模型模拟结果的差异性。实际生产表明,修正后的变粘度-多孔介质-临界固相率模型可以准确预测出铸件的浇不足缺陷,数值计算模型更可靠。

Misrun is one of the common casting defects in low-pressure casting of copper alloy.Numerical simulation can not only predict the final morphology of misrun,but also further analyze the formation and evolution of misrun.The key to predict misrun is to deal with the effect of alloy mushy zone on flow behavior.The model of variable viscosity-porous medium-critical solid fraction of copper alloys in the mushy region was modified,and based on the parameters of variable physical properties,the simulated results between it and the model of variable viscosity-critical solid fraction were calculated and analyzed comparatively.The actual production shows that the modified model of variable viscosity-porous medium-critical solid fraction can predict accurately the misrun defects,and the numerical calculation model is more reliable.