Study of Solidification Process of Ni-Based Superalloy Castings Manufactured in Industrial Conditions with the Use of Novel Thermal Insulating Module Technique

Abstract

The solidification process of IN713C Ni-based superalloy rod castings made by the investment casting method without and with the use of novel insulating module applied on the ceramic mold was studied in this article. The design of the cone-shaped insulating module was developed based on numerical simulations of the distribution of local solidification parameters, ensuring the lowest centerline shrinkage porosity along the castings. The effectiveness of the design of the insulating module was tested in industrial casting trials. It was found that the use of a novel insulation module increases temperature gradient G and decreases cooling rate v, thus leading to a favorable increase of the Niyama criterion value (Ny = G/√v) and also ensuring directional solidification of the casting rod compared to the process where thermal insulation was not used. In this way, the centerline shrinkage porosity was removed, maintaining the equiaxed grain structure of the castings. The presented results show that it is possible to use the same insulating module multiple times, in the subsequent manufacturing processes, to control the solidification of Ni-based superalloy precision castings in industrial conditions.