Influence of electromagnetic oscillation on casting defects and grain size in superalloy turbine guide castings

Abstract

The introduction of the electromagnetic oscillation (EMO) process has significantly improved the casting defects of the superalloy turbine guide castings, and the effect of EMO process on the defects, grain size, and tensile properties in superalloy turbine guide castings is also investigated. The results show that the EMO process ensures excellent mold filling of K477 and K536 superalloy turbine guide castings at lower preheating temperatures. The surface quality of K477 superalloy guide castings is significantly improved by EMO process, exhibiting almost no surface macroscopic shrinkage. Meanwhile, under the EMO process, the grain size of K536 superalloy turbine guide blades is reduced by over 46.75%, and the distribution of carbides and solid solution elements within the grains are improved, producing uniform, fine equiaxed grains across the blades. The elongations at room and high temperatures are increased by 24.78% and 46.4%, respectively.