Analysis on Failure Mechanism of Blade Fracture of Russia-made Turbine Unit

Through analysis methods such as chemical composition analysis,tensile test under high and normal temperature, microstructure analysis,microhardness analysis,and using fracture Scanning Electron Microscope(SEM)and Electronic Microscopic Data Process System(EDS),the fracture mechanism of blades in the 22th and 23rd stages has been tested.The comprehensive analysis of the test data shows that the blade fracture failure is resulting from the effect of fatigue fracture caused by alternative stress.Rough processing surface leading to stress concentration,and the fatigue property decrease resulting from poor microscopic organization are important causes of the blade fracture failure.