In view of the structural characteristics of the butterfly valve, the problems of unstable and easy deformation of the large middle sand core and difficult sand cleaning are solved from the aspects of process design, production and fixation of the sand core and the use of zirconium coating. The vent hole is set between the ventilation rope and the core head to avoid the possibility of pores in the casting. The foamed CERAMIC filter AND CERAMIC INNER runner technology are used in charge control and runner system to ensure the purity of molten iron. After several inoculated treatments, the metallographic structure and comprehensive properties of the casting meet the customer's standard requirements.
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