The conformable Meandering Winding Magnetometer (MWM®) eddy current sensors and MWM-arrays provide new inspection capabilities for gas turbine components. The sensors provide measurements of coating thickness and absolute electrical conductivity, which can capture features of interest for a population of components, e.g., for tracking fleetwide trends in quality and aging, failure evaluations, and correlating failure origins to features of specific fleet population segments. Inspection applications include metallic and nonmetallic coating thickness and porosity measurement, detection of cracks on complex surfaces, imaging and detection of small flaws, thermal degradation monitoring, and cold work quality assessment. For example, the U.S. Air Force uses the MWM for cold work quality control on all of the C-130 propeller blades that go through the Warner Robins ALC. For P-3 and C-130 propeller blades, trend analysis is being performed fleetwide. This paper describes MWM technology advances for absolute property measurements and specific capability demonstrations. Multifrequency quantitative inversion methods used for coating characterization are also used for characterization of process-affected zones, such as shot peen quality or titanium alpha case characterization.

Issue Section:
Gas Turbines: Industrial and Cogeneration
Keywords:
eddy current testing, gas turbines, nondestructive testing, inspection, thermal barrier coatings
Topics:
Coatings, Eddies (Fluid dynamics), Electrical conductivity, Gas turbines, Sensors, Thickness measurement, Quality control
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Copyright © 2002
 by ASME
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