Erosion Damage to Last-Stage Compressor Disk of a Heavy-duty Gas Turbine Engine

In the course of a service life extension after 100 000 operating hours, the rotor of a heavy-duty gas turbine was inspected. During the visual inspection, some compressor wheel disks, particularly in the last stage, showed conspicuous features and flawed material. The only causal damage mechanism worth considering is erosion: only very little deformation was found in the metallographic sections' microstructure immediately underneath the flawed material areas (wear or deformation induced damages would have lead to more deformation) and, what is more, the microstructure showed no evidence of corrosion. In accordance with VDI guideline 3822, the exact designation of the damage mechanism is "Flow wear in the form of sliding jet wear in the two-phase mixture gaseous/solid".