铸型透气性对生产合格消失模铸件至关重要。分别讨论了影响干砂和涂层透气性的因素 ,指出干砂最好选用平均细度为 2 5～ 45的圆形砂子 ,粒度分布应该集中。涂料要注意选择合适的耐火材料和粘结剂 ,并注意控制使用时的涂料密度 ,涂挂次数最好为一层 The breathability of the mold is essential for the production of ductile castings. The factors affecting the permeability of dry sand and coating are discussed respectively. It is pointed out that the best choice of dry sand is round sand with an average fineness of 25 ~ 45, and the particle size distribution should be concentrated. Paint to pay attention to select the appropriate refractory materials and adhesives, and pay attention to control the use of paint density, coating the best number of layers for a layer