Eddy current testing ect is one of the most popular nondestructive testing ndt techniques, especially for conductive materials. Faraday was a chemist in england during the early 1800s and is credited with the. Eddy current ndt thread inspection demonstration youtube. Pulsed eddy current pec has been successfully deployed over the last decades for a variety of corrosionrelated applications, most notably for corrosion under insulation cui inspections, corrosion under fireproofing cuf and flow accelerated corrosion fac. It begins with general electrical theory, and includes eddy current test principles, and discussions of coils, instruments and standards, and impedance plane response. Squids have been successfully applied for eddy current testing in numerous other application areas. Rao nondestructive evaluation division metallurgy and materials group indira gandhi center for atomic research kalpakkam 603 102, tn, india email. Several other methods such as remote field testing rft, flux leakage and barkhausen noise also use this principle. This is the basis of eddy current testing, by monitoring the voltage across the coil in such an arrangement we can detect changes in the material of interest. Uniwest offers full service and support for all our ndt, eddy current testing equipment, and application development processes. The rate of decrease of the eddy currents is monitored by the pec probe and is used to determine the wall thickness. It is mathematically convenient to define the standard depth of penetration where the eddy current. 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 ndt method slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising.
Ndt testmaker questions data base b supplements to recommended practice snttc1a question and answer books b. Eddy current technique is an important electromagnetic nondestructive evaluation technique that is widely used in power, aerospace, petrochemical and other industries for detection of. Pulsed eddy current pec has been successfully deployed over the last decades for a variety of corrosionrelated applications, most notably for corrosion under insulation cui. Pdf nondestructive techniques are used widely in the metal industry in order to control the quality of materials. The eddy currents diffuse inwards and decrease in strength. As you will see, eddy currents are small circulating electrical currents that are induced in conductive materials when a coil with an alternating current is placed near the. Scope this presentation is intended to give the participants an information importance and applications of one of the ndt technique known as eddy current technique non destructive testing qad outline.
The eddyfi spyne is an adaptable surface eca screening tool designed. Nondestructive techniques based on eddy current testing mdpi. Eddy current array eca, a digital electromagnetic ndt technique, has proven to be a more efficient alternative. Eddy current software solutions for more than 50 years zetec has been leading the way in nondestructive examination nde with inspection solutions, including our eddy current. This limits the sensitivity of eddy current method to the surface of the. The current in the coil generates circulating eddy currents in the specimen close to the surface and these in turn affect the current. Nondestructive testing ndt is a mechanism used by engineers to detect defects in materials and structures, either during manufacturing or while in service. Eddy current testing ct65, general dynamicsconvair division, 1979 b. Eddy current testing is one of the most extensively used nondestructive techniques for. Pdf eddy current technique is an important electromagnetic nondestructive. The test equipment consists of a generator ac power supply, a test coil and recording equipment, e.
Nondestructive testing solutions and technologies eddyfi. Eddy current testing has its origins with michael faradays discovery of electromagnetic induction in 1831. Eddy current inspection is an economical, nondestructive alternative to magnetic particle inspection. Eddy current inspection is one of several ndt methods that use the principal of electromagnetism as the basis for conducting examinations. Pulsed eddy current pec technique is a key nondestructive testing ndt method to identify the discontinuities in metallic structures for more than five decades 1,2. Owing to the fact that the eddy current problem is a low frequency electromagnetic field problem, the choice was the acdc module. Note that cracks must interrupt the surface eddy current flow to be detected. The purpose of this volume is to present the basic concepts of eddy currents, to explain how eddy currents are generated and distributed, to point out how the specimens magnetic and electrical effects relate to eddy currents, and. We hire, train, and maintain the most qualified people in. The aim of this project is to develop an electronic system that makes use of multiplexing techniques applied to eddy current non. Electromagnetic methods such as eddy current, magnetic particle or radiographic and ultrasonic methods all introduce. Eddy current testing is a modern nondestructive testing ndt method and prime tool in controlling quality of components for aerospace, automotive, heat exchanger tubes, pipes for oil, gas and structural applications at various stages of manufacturing and inservice inspections for surface and subsurface crack testing. Using the ether nde aerocheck eddy current ec flaw detector to demonstrate thread inspection in non destructive testing ndt. Electronic system for nondestructive testing using eddy.
In eddy current testing, a coil carrying an ac current is placed close to the specimen surface, or around the specimen. Simulation of eddy current non destructive testing using. This technology has proven to be an efficient screening tool, allowing for detection of corrosion without having to remove. Eddy current as an alternative to magnetic particle. This text was developed for instruction in eddy current testing.
Eddy current testing can be used on all electrically conducting materials with a reasonably smooth surface. Pancaketype probes can be used in either manual or automatic eddy current testing. As a result of electromagnetic induction, eddy currents will be generated in the pipe wall. Fundamentals of eddy current testing download ebook pdf. Pdf nondestructive techniques based on eddy current testing. Several other methods such as remote field testing. Eddy current probe catalog introduction 6 every section in this probe catalog begins with a short description of the different eddy current products available. Eddy current testing permits crack detection in a large variety of.
Nondestructive techniques based on eddy current testing. Eddy current inspection is one of several ndt methods that use the principal of. Eddy current inspection is fast, reliable, easy to use, and can inspect directly. Eddy currents are fields of alternating magnetic current that are created when an alternatin. In all cases, the agreement between theoretical results experimental measurements is excellent. This section gives a short description on how to build a probe part number. Eddy current method for the assessment of crack depths in metallic.
Typically, the methods used are ultrasonics, radiography, magnetic particle, eddy current. Eddycurrent testing an overview sciencedirect topics. The eddy current density, and thus the strength of the response from a flaw, is greatest on the surface of the metal being tested and declines with depth. Eddy current ec testing is a no contact method for the inspection of metallic parts. Research and application of pulsed eddy current testing for ferromagnetic metallic components 201607 a signal enhancement method for magnetostrictive guided wave testing of pipeline. Secondly, the eddy current ec technique is implemented. Magnetic methods barkhausen article detection of burning area in ferromagnetic material by eddy current, barkhausen noise and multi technical 3ma methods. Eddy current nde is commonly used in the inspection of. Eddy current technique is an important electromagnetic nondestructive evaluation technique.