The gating-riser system design used for using EPC process to produce the DN300 flange swing-opening type back pressure valve casting was introduced. Both the lop and bottom flowing-hole flanges were put in the horizontal position, the middle flange was put in the side position and ingales were set at its lower part, and in addition, several small slag-collecting risers were set on the top flange. The calculating-determined pouring time was 18.96 s. The EPS pattern was used for molding, the density of the pre-expanded plastic grains was of 23~26 g/dm3; 1.5 t KGPS medium frequency induction furnace was used for melting; tapping temperature was 1 550~l 580 °C; the nodularizing treatment was completed by one time tapping, and one time inoculation was adopted; the negative pressure for pouring was kept in the range of 0.06-0.065 Mpa for 5 min. The production result showed that using EPC process to produce big diameter back pressure valve castings has obvious technical and economical advatages.%介绍了用消失模工艺生产DN300法兰旋启式止回阀阀体铸件的浇冒口系统设计:将上下通径法兰水平放置、中法兰侧置,在其侧面下部设置内浇道,并在上法兰顶面设置集渣小冒口,浇注时间计算值为18.96 s；采用EPS模具成型,珠粒预发密度23～26 g/dm3;选用1.5t KGPS中频感应炉熔炼铁液,出铁温度1 550～1 580℃,一次孕育的球化处理工艺,浇注负压控制在0.06～0.065 MPa,保压5 min.生产结果表明,消失模铸造生产大口径止回阀类铸件具有明显的技术经济优势.
展开▼
