It is of practical interest to infer residual-stress information from the gas turbine compressor diaphragm (an assembly of a row of airfoils welded into inner and outer shrouds), using nondestructive methods. Residual stresses can build up as the airfoils are welded into shrouds. Magnetic hysteresis and Barkhausen effect measurements are particularly suitable for this purpose due to their high sensitivities to the stress-induced magnetic anisotropies. We report here on laboratory calibration measurements including a qualitative comparison with theoretical predictions. Field measurements are compared with results obtained using destructive techniques.
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