This wire produces a magnetic field around itself in the direction ascertained by the righthand rule. In this technique, a coil also called probe or sensor is excited with sinusoidal alternating current. Eddy current inspection is a noncontact procedure that is unaffected by the presence of oils, paints and coatings on the test specimen. Each individual eddy current coil in the probe produces a signal relative to the phase and amplitude of the structure below it. Several other methods such as remote field testing rft, flux leakage and barkhausen noise also use this principle.
Though it is considered as modern ndt method that has excellent capabilities beyond crack detection, it is obvious that there are limitation of using eddy current testing. Rft is primarily used to inspect ferromagnetic tubing since conventional eddy current techniques have difficulty inspecting the full thickness of the tube wall due. Our eddyfi peca hr probe was recently put to the test and the results even surprised our own team. Pdf eddy current technique is an important electromagnetic nondestructive evaluation technique that is widely used in power, aerospace, petrochemical. Eddy current nde is commonly used in the inspection of conducting samples. Similarly, eddy current testing of wires of arbitrary length. Frequently used for onsite inspection for corrosion in heat exchangers tubes, eddy current testing is very fast making it ideal for high volume. Assessment of eddy current testing for the detection of. Nondestructive examination nde technology and codes student manual chapter 9. In this technique, a coil also called probe or sensor is excited with sinusoidal alternating current frequency, f, 50 hz5 mhz, 100 ma.
The technology is based upon electromagnetic induction originally discovered by michael faraday in 1831. At that time, no other technology to detect these defects was available. Ect began largely as a result of the english scientist michael faradays discovery of electromagnetic induction in 1831. Encircling and sector eddy current coil tests perform in this manner. Eddy currents are fields of alternating magnetic current that are created when an alternatin. The sensitivity of such measurements is hindered by the materials low conductivity and high coherent background material noise, making the high sensitivity standards required by industry harder to achieve. Industrial eddycurrent testing ect inspections of aerospace superalloys, such as titanium 6al4v, must reliably detect submillimetre surface breaking defects. Eddy current ec testing is a no contact method for the inspection of metallic parts.
An instrument probe is placed on the weather sheeting insulation, coating or rusted surface of a pipe or vessel. This new textbook edition comes in hard cover with lamination for longer durability. In its most basic form the singleelement eddy current testing probe a copper wire is excited with an alternating electrical current. Buckley, formerly of hocking ndt introduction scope this document is intended as a brief familiarisation course for hocking ndts customers and sales representatives. Principle ec testing works on the principles of electromagnetic induction. Eddy current array eca is a nondestructive testing technique that provides the ability to electronically drive multiple eddy current coils, which are placed side by side in the same probe assembly. Eddy current testing is a nondestructive testing method widely used to examine tubing in heat exchangers, steam generators, condensers, air coolers and feedwater heaters. It can also be used to find flaws in the volume of structures of nonferritic metal. The principle of the eddy current technique is based on the interaction between a magnetic field source and the test material. Eddy current testing can be used for a wide range of applications, and is often applied for surface crack detection and material sorting. Chapter 5 basic electrical concepts related to eddy current testing.
Eddy current testing is an inspection method that can be used for a variety of purposes including the detection of cracks and corrosion, material and coating thickness measurement, material identification and, in certain materials, heat treatment condition. Magnetic field induces currents eddy currents in test specimen. In this study the amount of the pearlite content is analyzed using the eddy current testing response. Ndte 2401 nondestructive testing technology 3wldndt associate of applied science degree. The type of testing performed, using comprehensive throughtype coils or rotating probes, depends on the type of defect. Pulsed eddy current testing pect inspection technique innospection limited unit 1, howemoss avenue, kirkhill industrial estate, dyce, ab21 0gp, aberdeen, united kingdom. Eddy current testing of tubes is an effective way of assessing the condition and lifespan of tubes, particularly in the power generation, petrochemical, chemical, fertilizer. The eddy current testing programmed instruction series is two volumes which provide the background material you will need before you perform actual eddy current testing. Although testing with eddy cur rents is regarded as one of the major methods for nondestructive inspection, many people in the industry regard this technique as. Nondestructive techniques based on eddy current testing mdpi.
Pulsed eddy current nondestructive testing and evaluation. Eddy current testing ect is a well established technology for the inspection of metallic components for surface breaking flaws. We conduct pulsed eddy current testing and inspection according to the following steps. Click download or read online button to get fundamentals of eddy current testing book now. Pdf nondestructive techniques based on eddy current testing. Zetec eddy current technology and products provide a fast efficient solution for near surface anomalies in conductive material. The test equipment consists of a generator ac power supply, a test coil and recording equipment, e.
This quantum leap in eddy current technology, unique to ibg worldwide, establishes a new standard for quality in crack and grinder burn detection by the eddy. Assessment of eddy current testing for the detection of cracks in cast stainless steel reactor piping components pacific northwest national laboratory u. The product is passed through or adjacent to an electrical test coil, which. In this technique, a coil also called probe or sensor is excited with sinusoidal alternating current frequency, f, 50 hz5. Eddy current testing ect as a technique for testing finds its roots in electromagnetism. Each individual eddy current coil in the probe produces a signal relative to the phase and amplitude of the. It is not intended as a complete theoretical course in eddy.
This book is designed for nondestructive testing ndt technicians, engineers, and technical people interested in learning eddy current array eca principles and applications. The current generates a magnetic field around the coil. Eddy current testing equipment contains a conductive metal coil which is electrified with an alternating current. It detects material discontinuities and imperfections such as cracks, laminations, pores or. To accommodate advancements in ndt technology, later versions of this publication were issued in 1991, 2002 and 2008, the current. Nondestructive testing solutions and technologies eddyfi. Fundamentals of eddy current testing download ebook pdf. Nde technology and codes student manual table of contents usnrc technical training center rev 01039. It is used for component testing in the aviation and automotive industry. Pec technology allows measurements to be made through insulation, concrete or corrosion barriers. Ec testing works on the principles of electromagnetic induction.
An introduction to eddy current testing theory and technology joseph m. Eddy current testing is a nondestructive inspection technique proven for flaw identification, as well as for verification of proper heat treatmaterial structure and component features. Eddy current testing can be used on all electrically conducting materials with a reasonably smooth surface. Monday, february 17, 2020 thursday, february 20, 2020. Eddy current array eca is a nondestructive testing technology that provides the ability to electronically drive multiple eddy current coils, which are placed side by side in the same probe assembly.
Eddy current testing plays an important role in numerous industries, particularly in material coating, nuclear and oil and gas. Measurement and control challenges in improving the the. This magnetic field oscillates at the same frequency as the current running through the coil. The product is passed through or adjacent to an electrical test coil, which has been excited by an alternating current.
The eddy current technology as per din en iso 15549 is a nondestructive and contactless method for test ing materials. Eddy current testing technology 1st edition be exceptional 9 7 8 0 9 9 1 7 0 9 5 2 6. Eddycurrent testing an overview sciencedirect topics. Eddy current testing is a nondestructive method for testing metal surfaces for defects such as longitudinal and transverse cracks. Pdf pulsed eddy current nondestructive testing and. Available from the national technical information service.
Eddy current array technology the british institute of. Nondestructive testing eddy current basic principles. This induces a flow of eddy currents around the test material or in the case of a sector coil, in the area under the coil. Semiconductor detecting devices are not used very extensivelyin eddy current testing, but there has been a lot of research and development with semiconductor devices. Ndte 1440 eddy current testing 4 ndte 2401 advanced ultrasonics 4 subtotal 12 level 2 certificate total 45 capstone experience. Squids have been successfully applied for eddy current testing in numerous other application areas. However, the eddy current testing technique still needs to focus on the details of probe structure and its application.
What are the main limitations of eddy current technology. Eddy current testing technology iii table of contents. We offer a variety of pulsed eddy current pec and pulsed eddy current array peca probes to meet the toughest challenges of your critical structure inspections. Eddy current testing technology eclipse scientific. Eddy current testing technology 1st edition be exceptional 9 7 8 0 9 9 1 7 0 9 5 2 6 isbn 9780991709526. Notice the spike in the eddy current signal, confirming that there is a defect in the component. Pulsed eddy current testing pect is an inspection technique used for corrosion under insulation cui. Eddy current inspection is one of several ndt methods that use the principal of electromagnetism as the basis for conducting examinations. Eddy current testing is one of the most extensively used nondestructive. Theory and practice of non destructive testing 24,667 views. Nuclear regulatory commission office of nuclear regulatory research washington, dc 205550001. However, eddy current techniques that employ either fixed or rotating probecoil assemblies may be used to either enhance discontinuity sensitivity on the large diameter tubular products or to maximize the response received from a. The eddy current technology the eddy current technology as per din en iso 15549 is a nondestructive and contactless method for testing materials. Eddy current technique is an important electromagnetic nondestructive evaluation technique that is widely used in power, aerospace, petrochemical and other.
A magnetic field from a coil is induced into conductive material where anomalies in the material create changes to the eddy currents that are sensed for evaluation by specialized instrumentation. Pulsed eddy current testing pect inspection technique. Highsensitivity eddycurrent testing technology for. However, there are several major differences between eddy current testing and remote field testing. Pdf nondestructive techniques are used widely in the metal industry in order to.
The main goal is to outline the material needed for a first course in eddy current array technology. In 1983, eddy current technology incorporated developed a probe capable of detecting circumferential cracks at the tube sheet expansion transition zone. This greatly reduces preparation time prior to inspection. The test method can be optimally integrated in the production process. The eddy current method is widely used to inspect metallic aircraft components for surface cracks and corrosion damage.
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