Eddy Current Examination of Fatigue Cracks in Inconel Welds

2006 ◽  
Vol 129 (1) ◽  
pp. 169-174 ◽  
Author(s):  
Weiying Cheng ◽  
Ichiro Komura ◽  
Mitsuharu Shiwa ◽  
Shigeru Kanemoto
Keyword(s):  
Eddy Current ◽  
Nuclear Power ◽  
Power Plants ◽  
Base Alloy ◽  
Fatigue Cracks ◽  
Current Method ◽  
Destructive Testing ◽  
Eddy Current Method ◽  
Nickel Base ◽  
Basic Studies

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.

Analytical and Experimental Approaches for the Sizing of Fatigue Cracks in Inconel Welds by Eddy Current Examination

2004 ◽  
Author(s):  
Weiying Cheng ◽  
Ichirou Komura ◽  
Mitsuharu Shiwa
Keyword(s):  
Eddy Current ◽  
Power Plants ◽  
Base Alloy ◽  
Fatigue Cracks ◽  
Flaw Detection ◽  
Current Method ◽  
Nickel Base Alloy ◽  
Eddy Current Method ◽  
Experimental Approaches ◽  
Nickel Base

Cracks by SCC (stress corrosion cracking) and high cycle fatigue were detected at the welded joints of nickel based alloy of reactor vessel, pressurizer and core internal of nuclear power plants in recent years. To ensure the integrity of plants, it is necessary to improve NDT (non-destructive testing) techniques for reliable detection and evaluation of defects in the nickel-base alloy. Basic studies on the flaw detection and characterization by eddy current examination of inconel, a typical nickel-base alloy, are carried out. Specimens made of inconel and inconel weld metal are prepared, fabricated with EDM (Electro-Discharge Machining) notches and fatigue cracks. The detecting and sizing capability of eddy current method is investigated through analytical and experimental approaches. Numerical analysis helps in choosing an appropriate probe and examination condition, and evaluating a crack from the measured signals. All or part of a planar crack is reconstructed using an inversion approach. The result from ECT (eddy current testing) is compared with that of UT (ultrasonic testing). The research presented in this paper shows that by choosing a proper testing situation, eddy current examination is feasible for the detection and sizing of surface-breaking cracks in inconel welds.

scholarly journals Non–Destructive Testing of Conductive Material by Eddy Current Air Probe Based on Swept Frequency

2015 ◽  
Vol 66 (3) ◽  
pp. 174-177 ◽  
Author(s):  
Andrea Štubendeková ◽  
Ladislav Janoušek
Keyword(s):  
Numerical Model ◽  
Eddy Current ◽  
Current Method ◽  
Wide Frequency Range ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Eddy Current Method ◽  
Exciting Coil ◽  
Non Destructive ◽  
2D Numerical Model

Abstract This article deals with non-destructive testing of conductive materials by eddy current method based on swept frequency. A 2D numerical model of eddy current air-core probe was created in the LTspice software at first. The probe consists of two coils: exciting coil and receiving. The probe is positioned in air in this case. Experimental and calculated frequency responses of the probe are obtained within a wide frequency range using swept frequency in order to validate the model. Frther a 3D model used for non-destructive testing of austenitic steel plate with three electro-discharge machined notches is then developed accordingly. Results of measurement are compared with 3D numerical model using COMSOL Multiphysics software.

scholarly journals Extended Damage Detection and Identification in Aircraft Structure Based on Multifrequency Eddy Current Method and Mutual Image Similarity Assessment

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4452
Author(s):  
Tomasz Chady ◽  
Krzysztof Okarma ◽  
Robert Mikołajczyk ◽  
Michał Dziendzikowski ◽  
Piotr Synaszko ◽  
...  
Keyword(s):  
Image Quality ◽  
Eddy Current ◽  
Image Quality Assessment ◽  
Current Method ◽  
General Purpose ◽  
Reference Image ◽  
Destructive Testing ◽  
Eddy Current Method ◽  
Detection And Identification ◽  
Novel Approach

In this paper, a novel approach to Non-Destructive Testing (NDT) of defective materials for the aircraft industry is proposed, which utilizes an approach based on multifrequency and spectrogram eddy current method combined with an image analysis method previously applied for general-purpose full-reference image quality assessment (FR IQA). The proposed defect identification method is based on the use of the modified SSIM4 image quality metric. The developed method was thoroughly tested for various locations, sizes, and configurations of defects in the examined structure. Its application makes it possible to not only determine the presence of cracks but also estimate their size.

Initiation of PWSCC in Nickel Base Alloy 182

2013 ◽  
Author(s):  
Mickaël Wehbi ◽  
Jérôme Crépin ◽  
Thierry Couvant ◽  
Cécilie Duhamel
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Base Alloy ◽  
Nickel Base Alloy ◽  
Pressurized Water ◽  
Material Environment ◽  
Primary Water ◽  
Water Reactors ◽  
Nickel Base ◽  
Actual Initiation

To date, welded nickel base alloy 182 used in Pressurized Water Reactors (PWRs) components have shown a higher susceptibility to Primary Water Stress Corrosion Cracking (PWSCC) during laboratory tests than in power plants. However, an increasing number of cracks reported in American, Swedish and Japanese nuclear power plants on Alloy 182 enlighten the need for a predictive initiation model of PWSCC. Initiation of PWSCC involves several factors such as material, environment and loading history, interacting with each other. Building such a model first requires to focus on these parameters separately, in order to have a better understanding of the involved mechanisms at a local scale in crack initiation. This study focuses on the correlation between EBSD/strain field results to improve the accuracy of the actual initiation model [1] involving local parameters.

scholarly journals Use of non-destructive eddy current technique to detect simulated corrosion of aircraft structures

2020 ◽  
Vol 64 (2) ◽  
pp. 52-58
Author(s):  
M. Janovec ◽  
J. Čerňan ◽  
F. Škultéty
Keyword(s):  
Eddy Current ◽  
Current Method ◽  
Experimental Sample ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Eddy Current Method ◽  
Aircraft Structures ◽  
Aluminum Sheets ◽  
Riveted Joints ◽  
Non Destructive

AbstractThe article deals with the issue of non-destructive testing of riveted joints. In the article, the authors used a non-destructive eddy current array technique, which was applied to detect simulated corrosion in the field of aircraft riveted joints of aluminum sheets. In aircraft maintenance, the eddy current method is used to control the outer surface of the aircraft skin, especially the areas around the riveted joints. This method makes it possible to detect hidden cracks and corrosion that may occur during aircraft operation. Especially hidden are hidden cracks and corrosion of aircraft structures, which cannot be detected during a visual inspection of the aircraft. The aim of the experimental measurements was to reveal simulated corrosion in the area of riveted joints formed on the experimental sample. Corrosion was simulated by gluing aluminum powder to the surface of the aluminum sheets from which the sample was made. The simulated corrosion in the second and third layers of the riveted sample was reliably detected. The settings, the method of control and the results of measurements are given in the article in the experimental part and the results of measurements. Measurements were performed using a defectoscope with an ECA measurement module, with appropriate measuring probes suitable for this type of inspection.

scholarly journals Non-destructive testing of Al-Mg alloys by using the eddy-current method

2017 ◽  
Vol 106 ◽  
pp. 03007 ◽  
Author(s):  
Sergey Dmitriev ◽  
Alexey Ishkov ◽  
Alexander Katasonov ◽  
Vladimir Malikov ◽  
Anatoly Sagalakov
Keyword(s):  
Eddy Current ◽  
Current Method ◽  
Mg Alloys ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Eddy Current Method ◽  
Non Destructive ◽  
Al Mg Alloys

Taking Advantage of Signal Processing Techniques for the Life Management of NPP Components

2006 ◽  
Author(s):  
L. Chatellier ◽  
S. Dubost ◽  
F. Peisey ◽  
B. Richard ◽  
L. Fournier ◽  
...  
Keyword(s):  
Signal Processing ◽  
Eddy Current ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Industry ◽  
Destructive Testing ◽  
Small Surface ◽  
Plant Operator ◽  
Processing Techniques ◽  
Signal Processing Techniques

The long term management of nuclear power plants raises several major issues among which the aging management of key components ranks high, from both technical and economic points of view. In order to detect and characterize potential defects on cast components, a program of in-service inspections is carried out by non-destructive testing (NDT) methods. In general, defect detection is the first step of an inspection procedure. Should a defect be detected, the plant operator must evaluate whether the component should be replaced or repaired (now or later) and will be required to prove that the component still meets regulatory requirements. That is why the characterization of the defect in terms of locating and sizing is essential, especially when the proof relies on mechanical calculations. In this paper we provide an overview of advanced signal processing techniques based on regularization of inverse problems. Those techniques have a strong potential for improving defect positioning and sizing. This has already been demonstrated in several R&D studies in the field of radiography and ultrasonics, leading in some cases to expertise-oriented applications. After a presentation of the general principles, we detail how regularization can be applied to process eddy current probe signals and provide good estimates of the depth of small surface breaking defects. Encouraging laboratory results have been obtained so far, which may lead to re-consider the scope of the eddy current technique as presently used in the nuclear industry. For example, its eligibility as an alternative NDE method could be explored in cases dealing with this kind of defect, if ultrasonics failed to meet the required characterization performance.

Remote edge detection of subcutaneous stiffeners

2005 ◽  
Vol 219 (8) ◽  
pp. 579-585
Author(s):  
R Fenn ◽  
J C Watson
Keyword(s):  
Mild Steel ◽  
Eddy Current ◽  
Electrical Response ◽  
Plate Thickness ◽  
Current Method ◽  
Probe Design ◽  
Destructive Testing ◽  
Element Analysis ◽  
Eddy Current Method ◽  
Outer Skin

Construction of narrow-gap double skin components requires, at some stage, blind welding from one side. During construction, due to thermal distortion, the hidden stiffeners (spacers or stringers) may move sufficiently far from their designated locations that assembly welds, made from one side, could miss the stringers completely. Thus, a real-time sensor capable of identifying and accurately locating spacer edges beneath the outer skin is required. Outer skin magnetic properties and plate/spacer separation seriously influence the capabilities of the best candidate detecting methods. Initial trials were undertaken using a non-destructive testing (NDT) eddy current method to detect beneath aluminium plate. Probe design and construction concentrated on air-cored absolute coils, on which finite element analysis (FEA) was used to predict electrical response. When the refined detector system was tested on magnetic material (mild steel), it was found to be preferable if a static magnetic field was applied to the plate component. Applied magnetism had a profound effect on coil field penetration and hence detectability (maximum plate thickness rose swiftly from 3mm, unmagnetized, to over 12mm, magnetized). As a sensor, the eddy current detector was shown to be capable of finding subcutaneous edges in both aluminium and mild steel fabrications. What has been developed is a sensor simply requiring computer-controlled movement to allow completely automatic hidden edge finding.

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