Cracking Analysis of K465 Alloy Turbine Blade Body

Several K465 alloy turbine blades were found to have cracks in blade shroud and blade body by fluorescence inspection after test run in factory. Stereomicroscope and scanning electron microscope were used to analyze the crack morphology, crack fracture and metallographic structure of the blade. The results show that the nature of the crack is fatigue cracking, which originates from the surface of the inner cavity. The reason for the crack is that the application of the aluminum-based core casting and the improper module caused higher casting stress in certain position. By changing the aluminum-based core to a silicon-based core, improving the casting process and optimizing the module mode, the casting stress of the blade is reduced to prevent such failures.