AZ91镁合金负压消失模铸造充型速度的研究

真空度、浇注温度及模样厚度对AZ91镁合金消失模铸造充型速度影响的全因子实验的结果表明 ,它们都对充型速度起积极的作用 ,真空度是决定充型速度的一个关键工艺参数。在不抽真空时 ,充型速度非常小且随充型过程的进行逐渐降低 ,浇注温度对充型速度的影响也很小 ;抽真空时 ,充型速度在充型过程中不断变化且呈现不出任何规律 ,其起伏的幅度随真空度、浇注温度和模样厚度的增大而增大 ;在真空度较低时 ,随着真空度和 或浇注温度的提高 ,平均充型速度迅速增大 ,真空度与浇注温度对充型速度的交互作用增强 ;在较高的真空度下 ,平均充型速度仍随浇注温度的提高而增大 ,但平均充型速度的增大速率却随真空度的进一步提高而降低 ,真空度与浇注温度对充型速度的交互作用很弱。模样厚度对平均充型速度影响在抽真空时有所提高。

Study on mold filling velocity in AZ91 magnesium alloy LFC process with vacuum

Full factorial experiments were carried out to study the effects of vacuum, pouring temperature and pattern thickness on the mold filling velocity in AZ91 magnesium alloy lost foam casting (LFC) process. The results show: all of them play a positive effect on the velocity, and vacuum is a crucial parameter in determining the velocity. Without vacuum, the velocity is very small and continually decreases as the pattern is displaced, the effect of pouring temperature on velocity is minor; when vacuum is applied, the velocity during mold filling process varies greatly and displays indefinitely,and the fluctuation of the changing velocity increases with increasing vacuum, pouring temperature and the pattern thickness. At low vacuum, as vacuum and/or pouring temperature increase, the average velocity increases rapidly, and the interaction effect between vacuum and pouring temperature on the velocity is enhanced; at still higher vacuum, the average velocity increases with increasing pouring temperature all the same, but the average velocity increase rate decreases as vacuum further increases, and the interaction between vacuum and the pouring temperature is insignificant. The effect of pattern thickness on the velocity is somewhat modified under vacuum.