Non destructive testing with GMR magnetic sensor arrays
G. Cattiaux (1), F. Vacher, C. Gilles-Pascaud, J.M. Decitre, C. Fermon, M. Pannetier (2),
(1) IRSN, (2) CEA/LIST
9th European Conference on Non-Destructive Testing, Berlin, September 25-29 , 2006,
Rapport DSR 140
The inspection of material used in aerospace, nuclear or transport industry is a critical issue for the safety of components exposed to stress or/and corrosion. The industry claims for faster, more sensitive and cost–effective techniques. Technologies based on magnetic sensor with high sensitivity such as giant magneto-resistance (GMR) may be a good solution to improve the performances of the classical probes. The CEA has validated the performances of this technology for two kinds of applications in Eddy Current (EC) Non Destructive Testing. The first application deals with the detection of deeply embedded flaws. An EC probe based on GMR sensor has been developed and evaluated for the inspection of a 316 L stainless pipe section representative of the reactor residual heat removal (RHR) pipes. Cracks induced by thermal fatigue have been successfully detected under a ligament of 7 mm. In the second application, the very small size of the GMRs sensitive element (smaller than 100mm) is used to perform a very high-resolution probe. A GMR array probe has been thus specially designed by the CEA to detect small surface breaking flaws (100mm).