通过对不同壁厚的ZA27合金铸件在砂型铸造条件下凝固过程的观察，研究探讨了壁厚效应对砂型铸造ZA27合金组织、键全度和机械性能的影响。实验结果表明，随壁厚的加大，铸件键全度降低，由分散性缩孔趋向于集中性缩孔，显微组织有粗化趋势，机械性能降低；但随工艺因素的改变，壁厚效应可消除或消弱，在砂型铸造时严格控制其工艺参数，在壁厚小于60mm范围内均可获得优质铸件。 The effects of wall thickness on the microstructure, bond fullness and mechanical properties of sand casting ZA27 alloy were studied by observing the solidification process of ZA27 alloy castings with different wall thicknesses under sand casting conditions. The experimental results show that with the increase of the wall thickness, the overall degree of the castings decreases, the shrinkage shrinkage tends to concentrate shrinkage, the microstructure tends to roughen and the mechanical properties decrease. However, with the change of the process factors, the wall thickness The effect can be eliminated or weakened. During sand casting, the process parameters are strictly controlled. High-quality castings can be obtained in the range of wall thickness less than 60mm.