Influence of silicon carbide chills on solidification process and shrinkage porosity of castings made of nickel based superalloys

摘要

The paper presents the manufacturing methodology of IN713C castings by application of investment casting method and silicon carbide (SiC) chills. On the basis of numerical simulation and conducted microstructure analysis, it was established that the application of SiC chills results in significant decrease in shrinkage porosity, in comparison to castings without chills. The temperature measurement was carried out, and the influence of chills on the kinetics of solidification process was established. It was determined that the application of SiC chills causes the increase in cooling rate (～0.1 K s~(-1)), in comparison to the casting without chills. The authors carried out numerical optimisation with the use of ProCAST software and established which parameters have the largest influence on the solidification process of castings with and without chills. In addition to SiC, the graphite and Al_2O_3 were analysed as chill material in terms of influence on the predicted kinetics of cooling process and the shrinkage porosity of castings. The conditions of solidification process for castings, which are equipped with chills and are free from shrinkage porosity, were determined on the basis of obtained results.