Nondestructive Inspection of Hot Corrosion Damage on Internal Surfaces of Turbine Blades

Abstract

Two nondestructive techniques for the identification of hot corrosion damage on internal surfaces were investigated: magnetic permeability measurements and X-ray computed tomography (CT). A group of sixty-one Solar Titan 130 stage 1 blades, which were known to have hot corrosion damage on the internal surfaces at a specific location, were used for the investigation. X-ray CT was able to accurately identify the presence of hot corrosion as well as the extent to which it had progressed through the wall at the location of interest. The magnetic permeability technique was found to accurately identify whether hot corrosion damage had occurred at the location of interest, but could not as accurately determine the extent to which the damage had progressed through the wall. The results of the nondestructive testing were validated by destructive examination of some blades. The nondestructive testing methods evaluated through the study were able to determine the presence and extent of localized hot corrosion damage on internal surfaces, allowing for higher repair yields.