Failure analysis of stationary blades in a gas turbine compressor

During the GT13D gas turbine overhaul, there have been quasi-cracks in the stator blades of semi upper-end compressor rows that appeared in the grooves at the point where stator blades were attached to the roots. Also, due to the same phenomenon, the blade leading edge was damaged in the same area, which caused the replacement of a number of blades. In this paper, it has been tried to investigate these blades from different views and methods such as hardness, material, appearance, surface layers, microstructure, surface quality with SEM electron microscope and ... The dominant mechanism in erosion of this blade and the cause of this failure is determined. The results of these studies suggest that the martensitic stainless steel blade type is hardly uniform in all parts, and there are no structural changes indicative of temperature variations. Also, the erosion and deterioration factor can not be related to the presence of external particles. Studies have shown that the occurrence of the erosion phenomenon is likely due to the flow of air from the blades