钠磷变质ZL108合金圆柱体铸件中的晶粒尺寸

通过对钠，磷变质ＺＬ１０８合金圆柱体断面各测试点的取样，观测，对其显微组织晶粒尺寸及宏观缩孔，缩松的定量分析，并加以比较，认为磷变质的组织晶粒，缩孔和缩松对冷却速度要比钠变质的敏感得多。因此，在冷却速度大时（如金属型铸造或薄壁铸件）应采用磷变质；反之，对于冷却速度小的厚壁大件宜采用钠变质。

The Grain Size in Cylindrical Casting of ZL108 Alloy with Na or P Modifler

After sampling in measuring points of cylindrical casting section of ZL108 alloy with Na or P modifier, author observed the microstructure grain size of the specimens and made quantitative analysis to microstructure shrinkage cavity and porosity and compared with eath other. Author points out that the structure grain size, shrinkage cavities and porosities of ZL 108 allog with Pare more sensitive to cooling rate than that with Na. For this reason, under the condition of rapid cooling (for c(?)ample permanent mould casting or thin section casting), we had better use P as modifier, under the condution of slow cooling, It is better to use Na as modifier.