大型灰铸铁汽轮机缸体的铸造工艺设计

Casting Process Design of Large-Sized Gray Cast Iron Steam Turbine Cylinder

针对大型HT250汽轮机缸体的壁厚差别大,尺寸精度和表面粗糙度要求高等诸多难点,进行了砂型和制芯工艺方案设计,对两种工艺方案进行了分析和选定,并就选定的造型工艺进行了浇口、冒口、冷铁工艺设计。结合缸体铸造工艺设计要求,给出了合箱、熔炼、浇注和热处理等工艺的控制要点。按照工艺方案成功地生产出了大型HT250汽轮机缸体铸件,铸件品质达到工艺设计要求。

The sand mold and core making schemes have been made according to the characteristics of the large-sized stream turbine cylinder casting such as big thickness differences, high dimensional accuracy and surface roughness requirements and so on. Two of them were analyzed and one was selected, and the gating system, feeding system and chilling method have been designed for the selected scheme. Combining with the casting process design specifications for cylinder, the key control points of the mold assembling, melting, pouring and heat treatment processes were provided. After putting the scheme into practice, the large-sized HT250 steam turbine cylinder casting has been produced successfully, and the casting quality meets the requirements of the process design specifications.