Research on Impeller Foundry Technology

Author of the article:LI Xiaolong1,2, HUANG Peng1,2, NING Xianrun1,2

Author's Workplace：1. Yibin Push liandong Technology Co., Ltd., Yibin 644007, China; 2. Sichuan Power Components Manufacturing Engineering Technology Research Center, Yibin 644007, China

Key Words：impeller shrinkage; bottom gating system; impeller run fire; impeller slag

Abstract：Impeller is the core component of the fan. It is a thick nodular iron casting with uneven wall thickness distribution and complex hot joint distribution. In addition, the outer contour of the casting is processed by the whole body, and no casting defects are allowed, which makes the casting process difficult. To solve the problems of impeller shrinkage, slag defects and casting fire running, impeller casting technology was explored in this paper. The results show that the impeller castings can meet the requirements of MT (DIN EN 1369 Grade SM 3) and UT (DIN EN 12680-1 Grade 1), and the machining surface of the castings has no shrinkage porosity defects by optimizing the arrangement of chillers and risers to adjust the temperature difference of the cavity and reduce the tendency of shrinkage porosity. By adding filter pieces to the bottom injection gating system, the purity of molten iron can be improved, the molten iron filling is stable without slag rolling problems, and the impeller surface after processing has no slag inclusion defects. By adopting the horizontal casting process scheme, the problem of casting fire escape caused by a high static pressure head and large box expanding force during the graphitization expansion process can be effectively avoided. Overall, problems such as shrinkage of the impeller, slag defects and castings running fire can be solved to a great extent by optimizing the bottom injection pouring process of chillers and risers.