Investment Casting Defects of a Turbine Nozzle Made by K465 Alloy

The investment casting defects in a turbine nozzle with size of φ 331mm and thickness 0.7 mm and the number of vanes of 31 have been studied in two aspects, which were the porosity of the turbine nozzle’s inner cone and the cracks of the turbine nozzle’s vanes. ProCAST software was used to analyze the nozzle’s solidification process. A suitable gating system was used to solve porosity issues effectively by changing local thickness and improving solidification conditions. The crack on the nozzle’s vanes was studied and a kind of grain refiner was used to solve crack issues by improving shell strength. In order to manufacture castings with high metallurgical quality and meet the design and use demands, a reasonable gating system and a moderate shell process were used.