scholarly journals Investigation of welds by the method of the magneto-optical eddy current flaw detection

2018 ◽  
Vol 185 ◽  
pp. 02014 ◽  
Author(s):  
Nazar Lugovskoy ◽  
Vladimir Berzhansky ◽  
Dmitry Filippov ◽  
Anatoliy Prokopov ◽  
Alexandr Shuyskyy
Keyword(s):  
Mathematical Modeling ◽  
Magnetic Fields ◽  
Eddy Current ◽  
Eddy Currents ◽  
Flaw Detection ◽  
Current Method ◽  
Epitaxial Films ◽  
Eddy Current Method ◽  
Ferrite Garnet ◽  
Conducting Materials

The paper deals with the magneto-optical eddy current method of flaw detection of conducting materials, in which epitaxial films of ferrite garnet are used as sensors. In particular, the possibilities of visualization of welded seams in magnetic and non-magnetic samples, as well as the defectoscopy of the seams themselves, are considered. The second part of the work is devoted to mathematical modeling of the distribution of the magnetic fields of eddy currents near similar defects.

An Eddy-Current Method of Flaw Detection in Nonmagnetic Metals

1941 ◽  
Vol 8 (1) ◽  
pp. A22-A26
Author(s):  
Ross Gunn
Keyword(s):  
Eddy Current ◽  
Eddy Currents ◽  
Flaw Detection ◽  
Current Method ◽  
Test Sample ◽  
Current Pattern ◽  
Eddy Current Method ◽  
Recorded Performance ◽  
Alternating Magnetic Fields ◽  
Nonmagnetic Metals

Abstract An equipment suitable for the location of surface or submerged flaws in nonmagnetic metals is described. A predetermined pattern of electrical eddy currents is induced in a perfect test sample by alternating magnetic fields. Sensitive pickup coils properly disposed in relation to the eddy currents measure only the departures of the eddy-current pattern from the pattern in the perfect sample. The departures are indicated on a meter or may be recorded. Performance data are given for a universal type of search unit especially adapted for general surveys.

Hardness assessment of induction hardened layers based on the analysis of eddy current signal

2020 ◽  
Vol 24 (4) ◽  
pp. 3-9
Author(s):  
Dominik Kukla ◽  
Mirosław Wyszkowski
Keyword(s):  
Comparative Analysis ◽  
Cross Sections ◽  
Eddy Current ◽  
Eddy Currents ◽  
Induction Hardening ◽  
Current Method ◽  
Current Signal ◽  
Eddy Current Method ◽  
Lift Off ◽  
Non Destructive

The work concerns the assessment of the possibility of identifying changes in hardness of carburized and induction hardened layers using the eddy current method. The tests were carried out on three sets of samples, made of AMS 6414 steel, with different layer thickness, subjected to induction hardening and tempering in a wide temperature range, to obtain differences in layer hardness for each set. The samples of each set, with the layers with a hardness in the range of 760–920 HV, were subject to testes using eddy currents which consisted in the assessment of phase angle changes obtained as a result of the lift – off effect. Standard hardness measurements on the surfaces of the hardened layers were also carried out, and microhardness profiles were made on the cross-sections of the samples. The results of hardness measurements were subject to comparative analysis with the results of non-destructive tests and on this basis it was possible to identify changes in the hardness of layers, based on the results of non-destructive tests.

Grinding Burns Testing — New NDT Method? Do You Need Qualified Specialists for This?

NDT World ◽  
2021 ◽  
pp. 28-31
Author(s):  
Martin W. Seidel ◽  
Antje Zösch ◽  
Konstantin Härtel ◽  
Gunnar Morgenstern
Keyword(s):  
Eddy Current ◽  
Chemical Etching ◽  
Flaw Detection ◽  
Current Method ◽  
Machine Building ◽  
Theory And Practice ◽  
Final Exam ◽  
Eddy Current Method ◽  
Grinding Burn ◽  
Multi Stage

The highly loaded components used in machine building, automotive and aviation must have no thermal damage during grinding, the so-called grinding burn. In less loaded components, the grinding burn shall not exceed a certain level agreed between the manufacturer and the customer. In industrial practice, etching, Barkhausen-Rausch methods and eddy current are used to detect burns. To reliably perform inspection according to any of the methods, it is necessary that the flaw detection experts have sufficient knowledge and skills. This is particularly relevant for the multi-stage chemical etching process. In 2015, at the request of Turkish partners, IMQ developed the course "Inspection of grinding burns using chemical etching" in accordance with ISO 14104 and AMS 2649. Since then, more than 70 participants from several European countries have successfully completed this two-day course. In cooperation with DGZfP Ausbildung und Training GmbH, IMQ has developed a new course for the training of flaw detectors in the burns inspection during grinding. In addition to the etching method, the course included the eddy current method and the Barkhausen method, as well as liquid penetrant testing and magnetic powder testing. The content of the course, practical exercises and elements of the final exam in theory and practice are presented.

Eddy Current Method for Testing of Metals under Simultaneous Exposure to Radiation and Hydrogenation

2015 ◽  
Vol 1084 ◽  
pp. 16-20
Author(s):  
Vitalii V. Larionov ◽  
Andrey M. Lider ◽  
Yurii S. Bordulev
Keyword(s):  
Phase Composition ◽  
Eddy Current ◽  
Eddy Currents ◽  
Current Method ◽  
Metal Structure ◽  
Eddy Current Method ◽  
Simultaneous Exposure ◽  
Metal Hydrogenation ◽  
Diffusion Properties

The study demonstrated that implementation of eddy currents of different frequencies enables identification of altered phase composition, diffusion properties and metal hydrogenation extent. Using the newly developed parameters of eddy current method sensitivity, we have established that the change of a metal structure from one layer to another is identified by the currents of different frequency according to the depth of their penetration into a metal.

Determination of the Penetration Depth of Eddy Currents in Defectoscopic Tests

2013 ◽  
Vol 588 ◽  
pp. 64-73 ◽  
Author(s):  
Leszek Dziczkowski ◽  
Sławomir Zolkiewski
Keyword(s):  
Magnetic Field ◽  
Penetration Depth ◽  
Eddy Current ◽  
Eddy Currents ◽  
Current Method ◽  
Impedance Change ◽  
Depth Of Penetration ◽  
Eddy Current Method ◽  
Measuring Device

In the defectoscopic tests by means of the eddy currents method only a certain superficial layer of the tested element is inspected. The reason of this phenomenon is connected with a very important feature of the eddy currents. The induced eddy currents generate its own magnetic field which obstructs penetration for the primary magnetic field. It is crucial to know the penetration depth of eddy currents. It allows planning successfully the diagnosis process. There are two cases worth mentioning: when the eddy current method is treated as the additional method complementary to the ultrasound method (because it does not detect superficial defects) and when the eddy current method is used as the main method for the thin elements diagnosis. The most frequently used evaluation method of eddy currents penetration depth is connected with determination of the e-folding decrease of electric current. The definition is convenient to use because it is simplified by using in the mathematical formula (allowing determination of the depth) frequency of eddy current and conductivity of the diagnosed elements. However the simplifications are not sufficient in practice. When we change the frequency of eddy currents during the survey or the probe then the depth of penetration is also changed, then we can measure the depth of the defects. While measuring the conductivity of a proper material element it is obligatory to prepare an adequate size of the sample that is free of defects. Knowing the value of penetration depth is then very helpful. On the other hand, when we have a sample of a specified size and we want to measure its conductivity then the knowledge of the depth of penetration of eddy currents helps us to select the proper frequency. In the paper there is described a proposal of a different definition of the penetration depth of eddy current, much more useful and accurate according to the authors. To obtain much more precise results, the new eddy current method was proposed. This method takes into account not only the parameters of the diagnosed sample and the eddy current frequency but the characteristic of the measuring device as well. The above mentioned method is based on the universal mathematical model of impact of conductive thin foil on the measuring coil impedance change. The procedure of calculations is easy to carry out online.

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 Eddy current tomography for visualization of cracks in aircraft riveted joints

2021 ◽  
pp. 94-113
Author(s):  
Alexey Vertiy ◽  
Valentyn Uchanin ◽  
Vladimir Pavlikov ◽  
Simeon Zhyla ◽  
Olexandr Shmatko ◽  
...  
Keyword(s):  
Eddy Current ◽  
Eddy Currents ◽  
Near Field ◽  
Current Method ◽  
Electrical Current ◽  
Aviation Industry ◽  
Wave Band ◽  
Eddy Current Method ◽  
Millimeter Wave Band ◽  
Metal Products

The control of the subsurface areas of metal products is necessary in many technological processes. So, for example, in aerospace technology it is essential to determine the presence of defects in aircraft engines. The same problems arise in chemical, power and other industries, which are letting out the highly technological equipment one of the widely known methods for inspecting metal products in the aviation industry is the eddy current method. This method is widely used to control small microscopic defects inside conductive materials. This method allows to ensure the safety of the operation of various products and devices in many areas of modern industry. An eddy current detector (probe) is a device, which induces eddy currents into metal objects and then detects the magnetic fields produced by these eddy currents. A magnetic field is created by a coil, or set of coils, through which a time-varying electrical current is driven. The frequency regime is sufficiently low, a few hertz to a few hundred kilohertz, so the targets of interest are within the near field of the transmitter. Considering the high conductivity of study samples, we can define that used waves in metals are located in the millimeter wave band. An eddy current imaging can be considered near-field imaging and a device allowing obtaining the eddy current images as a scanning near-field microscope. The obtained experimental results showed that the proposed tomographic method is effective for studying various complex inhomogeneities under the metal surface

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