Eddy Current Examination of Fatigue Cracks in Inconel Welds

Abstract

Basic studies on the eddy current examination of defects in Inconel, a typical nickel-base alloy used in the reactor vessel, pressurizer, and core internal of nuclear power plants, are carried out. The detecting and sizing capability of the eddy current method is investigated through analytical and experimental approaches. Probe’s detectability is numerically evaluated, and appropriate probe and examination conditions are correspondingly selected. The numerical signal calculation and crack reconstruction approach is confirmed in terms of the study of the eddy current examination of electrodischarge machining notches in Inconel base metal, and further applied to eddy current examination of fatigue cracks in Inconel welds. The profiles of fatigue cracks are reconstructed using eddy current testing signals. Crack depths estimated by eddy current reconstruction agree well with that of ultrasonic testing and are consistent with the crack depths revealed from destructive testing. The research presented in this paper shows that by choosing a proper testing situation, eddy current examination is feasible for detecting and sizing of surface-breaking cracks in Inconel welds.