我厂生产台钻已二十多年,台钻立柱的铸造废品率一般在15~6O%范围内变动.立柱形状如图1所示,材质为HT20-40,平均壁厚18~25mm,毛重20~35kg(有几种规格).立柱长度方向大部分需磨光((?)8),表面不允许有渣孔、砂眼、气孔等缺陷.这是个典型的套筒类铸件, I plant production Taiwan has more than 20 years of drilling, drill column casting reject rate generally within the range of 15 ~ 6O%. Column shape shown in Figure 1, the material is HT20-40, the average wall thickness of 18 ~ 25mm, gross weight 20 ~ 35kg (There are several specifications.) Most of the length of the column to be polished ((?) 8), the surface does not allow slag holes, trachoma, porosity and other defects.This is a typical sleeve castings,