- Email: [email protected]
Deep penetration eddy current applications
London (United Kingdom), BISI-2412 (Translated from Materialprufung, Vol. 27, No. 7, pp. 189-190, 1985) The authors give general guidelines for the use of eddy current testing as described in DIN 54 144. They explain how the subject of this standard can be used for the solution of actual testing problems and therefore be of real use in everyday practice. 37401
Halgand, P.; Senevat, J.
Eddy current testing of zircaloy cladding Nuclear Europe, Vol. 7, No. 8/9, p. 19 (Aug./Sep. 1987) Various considerations have prompted the development of the method described to complement ultrasonic examination of the internal surface of Zircaloy cladding for fuel assemblies. 37400
Samman, J.; Launay, P.J.; Cherruau, F.
Non-destructive testing of PWR steam generator tubes in France Nuclear Europe, Vol. 7, No. 8/9, pp. 21-22 (Aug./Sep. 1987) A coherent strategy of non-destructive testing has been developed for the steam generator tubes in pressurized water reactors in France, based on understanding of the degradation phenomena. It involves coordinated action by the utility operator, the manufacturer and the service companies, and makes it possible to follow up precisely the possible evolution of degradation in tubes, while avoiding unnecessary plugging caused by arbitrary specifications. 37399
Holmstrom, J.-A.
On-line crack detection for hot slabs Asea Journal, Vol. 60, No. 2, pp. 12-15 (1987) In co-operation with Svenskt Stal AB (SSAB), Domnarvet, Sweden, Asea Metallurgy and Tornbioms Kvalitetskontroll AB have developed a system for detecting surface cracks in hot continuously cast slabs. The system, named Decracktor, is based on a special eddy current principle, where several measuring frequencies are used in combination with a unique transformation function. This makes it possible to detect both longitudinal and transversal cracks. Because cracks are detected directly during the casting, slabs free from cracks can be transferred immediately to the reheating furnace in the rolling mill without any further inspection. Another major step has consequently been taken towards the realization of continuous process from liquid steel to rolled product without any intermediate storage. Further, the ability of the system to detect surface cracks during casting means that the machine parameters of the continuous caster can be quickly adjusted, thereby improving the quality of the end product. As far as is known, Decracktor is the only system available on the market using the eddy current measuring principle and that stands up to the harsh conditions in the continuous caster environment. 37398
O. Connor, H.M.
Phased array eddy current inspection of expansion transition zones in steam generator tubing Canadian Society for Nondestructive Testing Journal, Vol. 8, No. 3, pp. 16, 18, 20, 22-23 (May/Jun. 1987) The Phased Array eddy current technique uses a unique bridge design and a unique probe design that has specific advantages for the inspection of expansion transition zones in tubing. The system has very little sensitivity to concentric variations such as expansion zones, support plates and tube sheets but has high sensitivity to defects due to their asymmetry. In addition, the method is sensitive to cracks whether they be axial or circumferential in orientation. This makes the system ideally suited to the detection of flaws at the expansion transition zone in steam generator tubing, especially for the detection of circumferential cracks at this location. This report describes how phased array eddy current technique works and gives several examples of the advantages of this system. 37397
Watson, P.C.; Cross, M.T.
Eddy-current testing and analysis of a sample of Zircaloy fuel cladding for the OECD Halden 'Round-Robin' exercise (Phase II) United Kingdom Atomic Energy Authority, Windscale Nuclear Power Development Laboratories, ND-R-1405(W)(R), 56 pp. (Feb. 1987) As part of an international 'Round-Robin' testing exercise organised by the OECD Halden Reactor Project in Norway, Windscale Nuclear Power Development Labs. were supplied with two samples of Zircaloy fuel cladding 37396
Simard, P.; Gaillard, P.; Chretien, J.F.
An attempt at automatization of an eddy current nondestructive testing Journal of Nondestructive Evaluation, Vol. 5, No. 3/4 pp. 109-118 (Dec. 1986) As a nondestructive testing, eddy currents are largely used by industry. Nevertheless, complete automatization of the devices are still unusual, especially those that are able to make a classification of the different kinds of defects likely to appear in the tested material. We propose a method based on a few simple hypotheses on the shape of the defect and the reaction of the probe which permits the extraction of information sufficient enough for classification. The analysis of the image of the defect which is obtained by the scanning of the tested piece involves two steps: (1) an analysis of the orientation and the shape of the defect and (2) the analysis of the relief of this image, which determines the position of significant features. The method has been tested on a given sample of population with a 80% rate of success. 37151
Yi, J.; Lee, S.
Flaw characterization in eddy current testing with lift-off variations of test coil
182
l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 115-121. Taylor Publishing Co., Dallas (1985). The problem on flaw characterization in eddy current testing with lift- off variations of a single-turn test coil above a conducting half space is examined. For the quantitative study, a formula is developed using Green's function technique. The range of the lift-off variation within which the effects of lift-off variation are negligible and flaw inspection is reliable, is studied. As a simple case, analytical expressions are obtained for a cylindrical flaw and spherical flaw coaxial with test coil within first order Born's approximation. 37150
Li, R.M.; Zhou, J.J.; Fang, H. Y.
Finite element analysis of eddy current feed-through probes l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 129-136. Taylor Publishing Co., Dallas (1985). The present paper describes qualitative analysis of eddy current feedthrough probes, results of finite element calculation and experimental verification. 37149
Stepinski, T.; Bergstrand, K.G.
Improved eddy current methods in hot steel testing l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 137-143. Taylor Publishing Co., Dallas (1985). The present paper is devoted to the recent developments in eddy current hot surface inspection systems obtained recently at AB Sandvik Bergstrand where a considerable effort has been made recently in the field of testing equipment for hot slabs, billets and bars. 37148
Crostack, H.-A.; Nehring, J.
Development and application of pulsed eddy current testing using CSTechnique l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 208-215. Taylor Publishing Co., Dallas (1985). A new pulsed eddy current method is presented. By the application of Controlled Signals (CS-Technique) transmitting pulses can be adjusted to specific test problems arising by completely adapting ampfitudes and phases in the interesting frequency range. Furthermore, beside the adjustment of frequency spectra, e.g. for narrowband pulses an even more complex signal processing method such as cross correlation analysis can already be integrated into the transmitting pulses. Thus, on-line signal processing is possible resulting in an significant increase of testing rates and also an essential reduction of the necessary expenditure of test equipment during in service testing. 37147
Houserman, H.E.; Lamb, L.T.
Eddy current testing using digital technology l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 234-238. Taylor Publishing Co., Dallas (1985). The presentation discusses some recent advances made in the area of 37146
Flora, J.H.
Deep penetration eddy current applications l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 253-260. Taylor Publishing Co., Dallas (1985). Deep penetrating eddy current inspection offers an order of magnitude improvement in ET penetration, allowing for the inspection of both sides of a material, even when covered by insulation. The DPEC technique is implemented via a microcomputer which generates the interrogating waveform and analyzes the return signal. Multifrequency mixing is used to minimize signals caused by variations in magnetic permeability and other unwanted variables. Low frequency probes can be configured for optimum performance for a variety of applications. 37145
Ports, F.; Carre, C.; Georgel, B.; Rose, C.;
Eddy current steam generator inspection equipment characterization and signal interpretation l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 274-280. Taylor Publishing Co., Dallas (1985). In the course of in-service inspection of steam generator tubes, various forms of eddy-current equipment are used. In particular, the probes are designed to comply with the specific constraints of this type of inspection (various types of defects, environment...). Differences exist within each family, chiefly in the technological choices made by the manufacturers. And yet it is necessary to be able to characterize and quantify the anomalies detected with sufficient precision and to be able to compare their development over successive inspections. So careful examination of in-phase and in-quadrature signals provided by the system is necessary. These signals take into account the characteristics of the EC system, the defects and the environment (tube, support plate...). The probe, in particular, has to be well suited to the problem and to give reproducible results. The study of its characteristics, in connection with mathematical modeling, makes the interpretation of EC signals easier. Once the system is well understood, signal processing methods allow elimination of noise, mainly due to irregularities of the inner diameter (pilgrim step).
NDT International June 1989
Halgand, P.; Senevat, J.
Eddy current testing of zircaloy cladding Nuclear Europe, Vol. 7, No. 8/9, p. 19 (Aug./Sep. 1987) Various considerations have prompted the development of the method described to complement ultrasonic examination of the internal surface of Zircaloy cladding for fuel assemblies. 37400
Samman, J.; Launay, P.J.; Cherruau, F.
Non-destructive testing of PWR steam generator tubes in France Nuclear Europe, Vol. 7, No. 8/9, pp. 21-22 (Aug./Sep. 1987) A coherent strategy of non-destructive testing has been developed for the steam generator tubes in pressurized water reactors in France, based on understanding of the degradation phenomena. It involves coordinated action by the utility operator, the manufacturer and the service companies, and makes it possible to follow up precisely the possible evolution of degradation in tubes, while avoiding unnecessary plugging caused by arbitrary specifications. 37399
Holmstrom, J.-A.
On-line crack detection for hot slabs Asea Journal, Vol. 60, No. 2, pp. 12-15 (1987) In co-operation with Svenskt Stal AB (SSAB), Domnarvet, Sweden, Asea Metallurgy and Tornbioms Kvalitetskontroll AB have developed a system for detecting surface cracks in hot continuously cast slabs. The system, named Decracktor, is based on a special eddy current principle, where several measuring frequencies are used in combination with a unique transformation function. This makes it possible to detect both longitudinal and transversal cracks. Because cracks are detected directly during the casting, slabs free from cracks can be transferred immediately to the reheating furnace in the rolling mill without any further inspection. Another major step has consequently been taken towards the realization of continuous process from liquid steel to rolled product without any intermediate storage. Further, the ability of the system to detect surface cracks during casting means that the machine parameters of the continuous caster can be quickly adjusted, thereby improving the quality of the end product. As far as is known, Decracktor is the only system available on the market using the eddy current measuring principle and that stands up to the harsh conditions in the continuous caster environment. 37398
O. Connor, H.M.
Phased array eddy current inspection of expansion transition zones in steam generator tubing Canadian Society for Nondestructive Testing Journal, Vol. 8, No. 3, pp. 16, 18, 20, 22-23 (May/Jun. 1987) The Phased Array eddy current technique uses a unique bridge design and a unique probe design that has specific advantages for the inspection of expansion transition zones in tubing. The system has very little sensitivity to concentric variations such as expansion zones, support plates and tube sheets but has high sensitivity to defects due to their asymmetry. In addition, the method is sensitive to cracks whether they be axial or circumferential in orientation. This makes the system ideally suited to the detection of flaws at the expansion transition zone in steam generator tubing, especially for the detection of circumferential cracks at this location. This report describes how phased array eddy current technique works and gives several examples of the advantages of this system. 37397
Watson, P.C.; Cross, M.T.
Eddy-current testing and analysis of a sample of Zircaloy fuel cladding for the OECD Halden 'Round-Robin' exercise (Phase II) United Kingdom Atomic Energy Authority, Windscale Nuclear Power Development Laboratories, ND-R-1405(W)(R), 56 pp. (Feb. 1987) As part of an international 'Round-Robin' testing exercise organised by the OECD Halden Reactor Project in Norway, Windscale Nuclear Power Development Labs. were supplied with two samples of Zircaloy fuel cladding 37396
Simard, P.; Gaillard, P.; Chretien, J.F.
An attempt at automatization of an eddy current nondestructive testing Journal of Nondestructive Evaluation, Vol. 5, No. 3/4 pp. 109-118 (Dec. 1986) As a nondestructive testing, eddy currents are largely used by industry. Nevertheless, complete automatization of the devices are still unusual, especially those that are able to make a classification of the different kinds of defects likely to appear in the tested material. We propose a method based on a few simple hypotheses on the shape of the defect and the reaction of the probe which permits the extraction of information sufficient enough for classification. The analysis of the image of the defect which is obtained by the scanning of the tested piece involves two steps: (1) an analysis of the orientation and the shape of the defect and (2) the analysis of the relief of this image, which determines the position of significant features. The method has been tested on a given sample of population with a 80% rate of success. 37151
Yi, J.; Lee, S.
Flaw characterization in eddy current testing with lift-off variations of test coil
182
l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 115-121. Taylor Publishing Co., Dallas (1985). The problem on flaw characterization in eddy current testing with lift- off variations of a single-turn test coil above a conducting half space is examined. For the quantitative study, a formula is developed using Green's function technique. The range of the lift-off variation within which the effects of lift-off variation are negligible and flaw inspection is reliable, is studied. As a simple case, analytical expressions are obtained for a cylindrical flaw and spherical flaw coaxial with test coil within first order Born's approximation. 37150
Li, R.M.; Zhou, J.J.; Fang, H. Y.
Finite element analysis of eddy current feed-through probes l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 129-136. Taylor Publishing Co., Dallas (1985). The present paper describes qualitative analysis of eddy current feedthrough probes, results of finite element calculation and experimental verification. 37149
Stepinski, T.; Bergstrand, K.G.
Improved eddy current methods in hot steel testing l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 137-143. Taylor Publishing Co., Dallas (1985). The present paper is devoted to the recent developments in eddy current hot surface inspection systems obtained recently at AB Sandvik Bergstrand where a considerable effort has been made recently in the field of testing equipment for hot slabs, billets and bars. 37148
Crostack, H.-A.; Nehring, J.
Development and application of pulsed eddy current testing using CSTechnique l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 208-215. Taylor Publishing Co., Dallas (1985). A new pulsed eddy current method is presented. By the application of Controlled Signals (CS-Technique) transmitting pulses can be adjusted to specific test problems arising by completely adapting ampfitudes and phases in the interesting frequency range. Furthermore, beside the adjustment of frequency spectra, e.g. for narrowband pulses an even more complex signal processing method such as cross correlation analysis can already be integrated into the transmitting pulses. Thus, on-line signal processing is possible resulting in an significant increase of testing rates and also an essential reduction of the necessary expenditure of test equipment during in service testing. 37147
Houserman, H.E.; Lamb, L.T.
Eddy current testing using digital technology l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 234-238. Taylor Publishing Co., Dallas (1985). The presentation discusses some recent advances made in the area of 37146
Flora, J.H.
Deep penetration eddy current applications l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 253-260. Taylor Publishing Co., Dallas (1985). Deep penetrating eddy current inspection offers an order of magnitude improvement in ET penetration, allowing for the inspection of both sides of a material, even when covered by insulation. The DPEC technique is implemented via a microcomputer which generates the interrogating waveform and analyzes the return signal. Multifrequency mixing is used to minimize signals caused by variations in magnetic permeability and other unwanted variables. Low frequency probes can be configured for optimum performance for a variety of applications. 37145
Ports, F.; Carre, C.; Georgel, B.; Rose, C.;
Eddy current steam generator inspection equipment characterization and signal interpretation l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 274-280. Taylor Publishing Co., Dallas (1985). In the course of in-service inspection of steam generator tubes, various forms of eddy-current equipment are used. In particular, the probes are designed to comply with the specific constraints of this type of inspection (various types of defects, environment...). Differences exist within each family, chiefly in the technological choices made by the manufacturers. And yet it is necessary to be able to characterize and quantify the anomalies detected with sufficient precision and to be able to compare their development over successive inspections. So careful examination of in-phase and in-quadrature signals provided by the system is necessary. These signals take into account the characteristics of the EC system, the defects and the environment (tube, support plate...). The probe, in particular, has to be well suited to the problem and to give reproducible results. The study of its characteristics, in connection with mathematical modeling, makes the interpretation of EC signals easier. Once the system is well understood, signal processing methods allow elimination of noise, mainly due to irregularities of the inner diameter (pilgrim step).
NDT International June 1989