Elimination of inclusion and shrinkage cavity in lost foam casting nodular cast iron reducer housing

Lost foam casting nodular cast iron has the advantages of good surface quality, high dimensional accuracy and high process yield. It is applied to the production of nodular cast iron. The reducer shell is required to have high strength, toughness, wear resistance and seismic performance, and the material is QT450-10. The casting of reducer shell weighs 112 kg, the thickest part of the wall is 54 mm and the thinnest part is 14 mm, and the geometric hot spots are concentrated. According to the equipment production capacity of the foundry and the characteristics of the casting, the lost foam casting process is selected.

(1) the inclusion defects due to incomplete cracking of foam materials are inevitable for EPC cast ductile iron. However, by adding the allowance to the end face of the cast iron, the inclusion is gathered inside the process allowance, and the workability allowance is removed. Finally, the qualified EPC ductile iron castings without inclusion defects are obtained.

(2) The shrinkage cavity of nodular iron castings produced by EPC is very difficult when using the traditional riser and cold iron process. Therefore, a new process method, heat sink process, is designed. A certain number of heat sinks are set at the hot joints of EPC nodular iron castings to strengthen the local heat dissipation speed, so as to eliminate the geometric hot joints of EPC nodular iron castings and solve the shrinkage defects of EPC nodular iron castings. The heat sink process has been verified by the reducer shell casting, which proves that the process meets the design requirements and can be solved

It is a new method to solve the shrinkage cavity in EPC nodular iron castings.

(3) The flexible chill process solves the problems of setting chill model cluster deformation in EPC nodular cast iron, and can effectively eliminate the shrinkage defect of EPC nodular cast iron.