WCNDT Durban, South Africa April 2012

Transcription

1 WCNDT Durban, South Africa 16 2 April 212

2 Innovative Flexible Eddy Current Probes for the Inspection of Complex Parts B. Marchand, JM. Decitre, O. Casula C. Ruaud 2

3 CONTEXT NDT using Eddy Current method: Powerful mean of detection of defects located into metal parts But, difficulties may arise when: Detection of small surface defects Fast, accurate and reliable inspection is required Located into complex geometries or hardly accessible areas Development of EC probes including Multi-elements: large matrix of sensors Flexibility Versatility Detection of sub-surface defects Low frequency required due to skin depth effect Located into complex geometries Development of EC probes including Large bandwidth sensors (GMR) Flexibility Able to detecting defects in magnetic materials 3

4 OUTLINE Development of flexible EC probes based on micro-coils Modeling and optimization using CIVA 1. software 1 example: Development of a 96-elements flexible probe EC probe for the inspection of SG tubes Development of EC probes based on magnetic sensors Modeling using CIVA 1. software 1 example: flexible GMR probe for sub-surface defects Use of magnetic sensor for the inspection of magnetic materials 4

5 FLEXIBLE AND MULTI-ELEMENTS EC PROBES Modeling of EC arrays probes using CIVA 1. Design of the elementary coil in layer #1 (diameters, turns,..) Design of the matrix in layer #1 (number of coils, pitch, ) Design of the layer #2 (coils and matrix) Definition of the functions (emitters, receivers, both) and wiring Definition of an elementary pattern (Nx emitters, Ny receivers) Definition of the sequences and frequencies Computation (including coupling between patterns) Exportation of the file containing the parameters MultiX-CF electronics device (M2M) 5

6 FLEXIBLE AND MULTI-ELEMENTS EC PROBES Development of flexible EC probes: 64 and 96 elements Objective : Development of an EC probe with the specifications: High density matrix sensors high spatial resolution Embedded electronic increase of the SNR Flexibility and versatility inspection of complex geometry or hardly accessible areas The head of the probe can be changed Its shape fits the geometry to be inspected Embedded electronic Sensitive area: 64 or 96 elements matrix manual or mechanical use Foam for flexibility Radius of curvature = 5mm / 1 mm / 35 mm This probe is shown on the CEA LIST s stand (#133) 6

7 FLEXIBLE AND MULTI-ELEMENTS EC PROBES Experimental results using the 96-elements flexible probe (1/3) Mechanical bench (encoder) Parameters Electronics = MultiX-CF from M2M Company (Emitter = 32 channels, Receiver = 64 channels //) Flexible and almost flat head (R = 35mm), 96 elements (192 µ-coils) f = 1 MHz 3 surface notches, L = 1mm, W =.1mm and H =.2mm,.4mm and.8mm (Aluminum mock-up) Experimental CSCAN 34mm element #96 notch #1 height.2mm notch #2 height.4mm notch #3 height.8mm element #1 7mm Flat head 96-elements 3 surface notches Aluminum mock-up Fast inspection: inspected strip width = 34mm High spatial resolution: pitch = 35µm Good sensitivity of the sensors 7

8 FLEXIBLE AND MULTI-ELEMENTS EC PROBES Mechanical bench (encoder) Experimental results using the 96-elements flexible probe (2/3) Parameters Electronics = MultiX-CF Flexible 96 elements probe f = 1 MHz Inconel mock-up Length (mm) Width (mm) Height (mm) notch # notch # notch # notch # mm Experimental CSCAN A A element #96 element #1 1mm [A-A ] line: detection of the four notches by one element of the array Flat head 96-elements 4 surface notches 4 flat-bottom holes Inconel mock-up 8

9 Mechanical bench (encoder) FLEXIBLE AND MULTI-ELEMENTS EC PROBES Experimental results using the 96-elements flexible probe (3/3) Parameters Electronics = MultiX-CF Flexible 96 elements probe f = 1 MHz Inconel mock-up Diameter (mm) Height (mm) hole # hole #2.2.2 hole #3.1.2 hole # mm Experimental CSCAN element #96 B B element #1 1mm [B-B ] line: detection of the four holes by one element of the array Flat head 96-elements 4 surface notches 4 flat-bottom holes Inconel mock-up 9

10 EC PROBES FOR THE INSPECTION OF SG TUBES Objective : Development of a EC probe for the inspection of Steam Generator Tubes Specifications High sensitivity micro-coil on Kapton film Flexible and fits the inner diameter of the tube Embedded electronic increase of the SNR Helical movement to cover all the inner wall of the tube centering brushes Sensitive area: micro-coil on flexible film Embedded electronic 1

11 Angle ( ) Angle ( ) Angle ( ) EC PROBES FOR THE INSPECTION OF SG TUBES Optimization of the probe thanks to CIVA 1. Optimization performed using elementary and composed defects Axial defect, length = 7mm, 1% Transverse defect, length = 6mm, 4% external «L» defect composed with - 1% axial defect - 4% external transverse defect f=24khz 45 Amplitude db 45 Amplitude +.6dB 45 Amplitude +2.1dB Z Z Z 1% - 7mm -45 Axis of the tube (mm) % ext 6mm Axis of the tube (mm) Axis of the tube (mm) 16 Good detection and recognition of the defects Low influence of the shape of the defects (rectangular or elliptical section) Characterization of the length of the defects 11

12 mm mm EC PROBES FOR THE INSPECTION OF SG TUBES Experimental results Parameters 6 5 SG tube (inconel) 18 3 defects f = 24kHz Voie : 24k Composante : X Equilibrage : aucun Normalisation : 1.79V -2.deg \\Dtasac1\disc\LIC\PROJETS\CF\ManipJLL\SondeTubeKaptonTournante-irsn21\tubeztdcea-14-24khz-defautall_lent.2d (1) Interpolation : Non Extraction : Oui Axe Orthonormé : Oui Echelle de Couleur Fixée : Oui Voie : 24k Interpolation : Non Composante : Y Extraction : Oui Equilibrage : aucun Axe Orthonormé -1 : Oui Normalisation : 1.79V -2.deg Echelle de Couleur Fixée : Oui -1 mm \\Dtasac1\disc\LIC\PROJETS\CF\ManipJLL\SondeTubeKaptonTournante-irsn21\tubeztdcea-14-24khz-defautall_lent.2d (1) 36 8 X 18 Y 1mm 1% axial 21 db 8mm 4% trans 2 db Both (a) (b) (c) (a) (b) mm de tournante kapton 24 khz non filtré Partie courante (c) 1% axial % axial 4% trans 4% trans Good detection and recognition of the defects (SNR ~ 2dB) Separation of the defects using the phase ( φ = 8 ) 12

13 EC PROBES BASED ON MAGNETIC SENSORS Modeling of the magnetic sensor (GMR) using CIVA 1. Magneto-resistance (MR) principle Variation of the resistance of the sensor with the applied magnetic field Parameters Definition of one or more magnetic sensor(s) Sensibility of the sensor(s) [V/T] GMR GMR Orientation of the sensitive axis (x, y, z) 13

14 Imaginary part Imaginary part Real part Real part EC PROBES BASED ON MAGNETIC SENSORS Modeling of the magnetic sensor (GMR) using CIVA 1. Configuration: - Inconel plate (1 MS/m), thickness = 1.55mm - Buried notch: L=1mm, W=.1mm, H=.9mm, Ligament =.62mm - Frequency: 1 khz Modeling of the EC probe: - Emitter: rectangular coil - Receiver: GMR along the X axis (component Bx of the magnetic field) defect defect scan Case n 1 : scan along the X axis (// to the axis of the defect) Case n 2 : scan along the Y axis ( to the axis of the defect) CIVA 1. EXP CIVA 1. EXP scan Impedance plane Impedance plane Good agreement between experience and simulation 14

15 EC PROBES BASED ON MAGNETIC SENSORS Flexible mono-element EC probe for the detection of buried defects GMR Large bandwidth Good sensitivity at low frequency Distance [Emitter / Receiver] optimized for the detection of buried defects Flexible EC probe based on GMR silicone Magnetic sensor: GMR Embedded into silicone Emitter : winding coil Flexibility inspection of non-planar parts (welding for instance) This probe is shown on the CEA LIST s stand (#133) 15

16 EC PROBES BASED ON MAGNETIC SENSORS Experimental results using the flexible GMR probe Configuration Stainless Steel cylinder mock-up (f ext = 134 mm, thickness = 12 mm, height = 14 mm) 7 axial notches located into the inner wall Length Height Ligament 2 mm 1 mm 2 mm 1 mm 4 mm 8 mm 6 mm 6 mm 8 mm 4 mm 2 mm 1 mm 4 mm 8 mm 6 mm 6 mm External inspection of the cylinder (use of a rotating mechanical bench) EC probe SST cylinder 16

17 Real part 2 mm Real part EC PROBES BASED ON MAGNETIC SENSORS Experimental results using the flexible GMR probe Defects L = 2mm, ligament: 2 to 8 mm mm 4 mm 6 mm mm Defects L = 1mm, ligament: 2 to 6 mm 8 mm mm 1 4 mm.5 6 mm mm 1 khz (d = 16 mm) 2 khz (d = 11 mm) 5 khz (d = 7 mm) 1 khz (d = 5 mm) Good detection of the defects (SNR > 15dB) 17

18 GMR PROBES FOR THE INSPECTION OF MAGN. PARTS Difficulties when materials are magnetic: Magnetic permeability low frequency is required Low frequency use of magnetic sensors (GMR) But GMR are disturbed by the residual magnetic field Experimental configuration: - 2 holes - magnetic material mock-up (16MND5) σ = 2.8 MS/m µ = 5 Hole #1: Φ: 5mm H: 2.5mm Area temporarily magnetized by a horizontal magnet Hole #2: Φ : 4mm H: 2mm z y x Experimental CSCAN at 7kHz: magnetic sensor without control loop Experimental CSCAN at 7kHz: magnetic sensor with control loop hole #1 Signature of the residual hole #2 magnetic field Better detection of hole #1 The signature of the residual Better detection of hole #2 magnetic field has disappeared 18

19 CONCLUSIONS Modeling with CIVA Modeling of high density matrix sensors Exportation of the parameters from CIVA to electronics device (MultiX-CF, M2M) Modeling of probes based on magnetic sensors, Flexible EC probes Probe for the inspection of SG tubes Detection of the defects with good SNR Low sensitive to the shape of the defect Transverse defects are identified using the phase of the signal 96elements EC probe Good sensitivity of the probes Fast inspection (1 scan is 34mm) High spatial resolution (high density sensors) EC probes based on magnetic sensors Good performances of the GMR probe (detection of a sub-surface defect with ligament 8mm) Effective control loop to use the GMR probe for the inspection of magnetic materials 19