Casting method for impeller made of super duplex stainless steel 5A material

The invention provides a casting method for an impeller made of a super duplex stainless steel 5A material. The method comprises the steps of preparation of a casting mould and a sand core, specifically, the casting mould and the sand core are prepared in the manner that alkaline phenolic resin is added to crude sand, the casting mould is provided with an impeller cavity for storing the sand core, and a dead head is internally provided with a ceramic foam filter; casting and pouring; and sand shakeout and heat treatment of a heat-filling furnace, and an impeller finished product is obtained. The temperature ranges of precipitation of brittle phases including Eta, Chi and Sigma can be avoided, precipitation of the brittle phases by an impeller casting structure is avoided, crack defects of an impeller casting are overcome fundamentally, density of the casting structure can also be guaranteed, and the yield rate of a casting finished product can be increased to 96% or above; and meanwhile, the casting production cost is greatly lowered as the technological yield is increased, and the heat-filling furnace process is implemented.