Porosity in Turbine Blades Cast into New Shell Moulds Made of SiC Based Ceramics

Abstract

The subject matter of the paper is the quantitative evaluation of gaseous and shrinkage porosity in the turbine blades using quantitative metallography methods. The research material consisted of blades with a polycrystalline structure made of IN 713C superalloys. Three different shell mould systems were used during the investment casting: shell A - typical industrial shell mould system and used in this work as the reference; shell B – similar to version A, but SiC grit was applied as back-up stucco; shell C – entirely SiC shell mould system. The blades of superalloy IN-713C cast into the wholly SiC shell mould system have revealed much lower porosity as compared to the blades cast into the typical industrial shell mould system.