罗茨鼓风机零件叶轮、轴承座、轮毂是关键性的零件,机械性能或加工精度都要求很高。设计规定这些铸件不允许有气孔、缩松、砂眼、夹渣等缺陷。我们采用砂型铸造,用本省冷水江铁作炉料。由于冷水江铁含磷比较高,一般都在0．4%以上,这几种铸件壁厚相差较大,因此往往在铸件热节部位产生缩孔、缩松等缺陷,造成铸件成批报废。 Roots blower parts impeller, housings, hubs are the key components, mechanical performance or processing precision are demanding. The design requirements of these castings do not allow pores, shrinkage, trachoma, slag and other defects. We use sand casting, with the province for cold water Jiang iron charge. Due to the relatively high phosphorus content in cold-water river iron, which is generally above 0.4%, the wall thicknesses of these kinds of castings differ greatly. Therefore, defects such as shrinkage cavities and shrinkage are often produced in the hot section of castings, causing the castings to be scrapped in batches.