- Email: [email protected]
Test rigs for magnetic flux leakage inspection tools for pipelines
N DT Abstracts The defect-inducedsignals obtained from magnetic flux leakage (MFL) pipeline inspectiontools are strongly dependent on stress induced in the pipe wall by the internal gas pressure. Precision MFL maps measured with and without 100 MPa tensile simulated line pressure stress are presented here and the changesare compared with stressconcentrationsaround a near side pit. 49984
found to increase linearly with the magnetizing frequency. The rate of increase of MAE rms voltage with frequency was found to depend on the magnitude of the magnetic flux density. The observed MAE waveforms have been analyzed in terms of the frequency dependence of their rms voltage and the muse-height distribution of MAE voltage oulses. With incre&ing magnetizing frequency, the smaller amplitude MAE pulses are replaced by large amplitude pulses, and the total number of MAE pulses also increases. The results are discussed in light of existing models of domain wall motion and magnetoacoustic emission.
Dhar, A.; Clapham, L.; Atherton, D.L.
Effect of sweep and bias field amplitudes on the magnetoacoustic emission IEEE Transactions on Magnetics, Vol. 27, No. 6, pp. 53645366
49520
49976
495 16
Yoshimoto, T.; Takahashi, M.
48522
48521
Bal, C.
Nestleroth, J.B.; Lindsay, B.B.; Davis, R.J.
Papenfuss, S.
International Petroleum Industry Inspection Technology II, Houston Texas (United States), 25-27 Jun. 1991. pp. 14-21. ASNT (1991) The conscientious pipeline operator must monitor many aspects of operational pipeline deterioration. Additionally, some operators must deal with pipelines containing manufacturing defects known as hardspots. A magnetic flux leakage tool readily detects regions of elevated hardness (hardspots) in line pipe.. Hardspots may be evaluated with a hardness tester and gauss meter. Repair of hard spots can be accomplished by pipe replacement or the installation of full encirclement weldover sleeves. By reliable detection of hardspots with flux leakage tool, and the appropriate on-site, post survey verification and repair, hardspot failures can be reduced, if not eliminated.
Pipes&Pipelines International, Vol. 37, No. 3, pp. II-15 (May-Jun. 1992) Misunderstandingscan occur between pipeline operators and inspection operators over the use of intelligent pigs and the preparation necessary before they are used. Possible causes for such misunderstandings are described by detailing all the activities required for a pre-inspection survey. Single pig runs will not necessarily produce conclusive information on pipe-wall surface conditions as the amount and speed of data collected are prodigous. Such pipe-line survey form only part of an overall maintenance programme and it is essential for the contractor to have access to relevant pipeline data so that the pig survey report format is compatible to the maintenance programme.
48508 A.
Dhar, A.; Atherton, D.L.
of
Edens, C. W.
Utilization of magnetic flux leakage inspection pigs for bardspot detection and repair
activities for magnetic-flux intelligent
dependence
installed
International Petroleum Industry Inspection Technology II, Houston Texas (United States), 25-27 Jun. 1991. pp. 9-13. ASNT (1991) Magnetic flux leakage (MFL) for metal-loss defect detection and characterization is the most completely developed and frequently used technology for in-line inspection (IL]) of natural gas pipelines. The focus of this paper is on the results of finite element modelling of the magnetic flux leakage phenomena. Signal features will be correlated against defect geometry to illustrate defect-signal relationships. For example, defect length can be estimated from peak amplitude location of the normal field. The effects of defect width, depth and shape on the estimation of length will be presented. Though these modelling results will provide an upper level of performance of MFL inspection technology, the general capabilities can be addressed.
Pipeline Pigging Technology, 2nd Edition, 1992. Edited by J.N.H. Tiratsoo. pp. 303-324. Gulf Publishing Company (1992) The advent of high-resolution magnetic-based on-line inspection and monitoring equipment now allows operators to thoroughly assess the integrity of a pipehne. This equipment can find all significant defects in the line, and it is then the operators’ responsibility to determine whether these defects require repair. The significance of many pipeline defects can be assessed using proven simple analytical methods. These methods can be applied to assessdefects detected in- service, or to plan inspection schedules for corroding pipelines. This paper describes the variety of pipe-wall defects that can be detected during pigging, and summarizes their assessment methods. The incorporation of these methods into condition-monitoring plans is discussed, and finally an overall defect assessment methodology is presented.
Magnetizing frequency emission in pipeline steel
of
Magnetic flux leakage signal analysis for metal-loss defect characterization
The assessment of pipeline defects during pigging operations
49717
inspection
Materials Evaluation, Vol. 50, No. 4, pp. 476-480 (Atp. 1992) Tradition techniques for inspecting oil country tubular goods (OCTG), such as electromagnetic inspection, are often inefficient at locating service-induced flaws and wail loss in drill pipe and tubing. The approach described in this article aims to overcome these difficulties using a solid-state, small-area detector. The increased sensitivity to flaws of devices provides a better opportunity to locate three dimensional defects. They are highly recommended to replace the less- efficient search coil and gamma ray tools currently used in electromagnetic inspection systems.The use of semiconductors as flux sensors lead to better quality control of used tubular products.
Hopkins, P.
Pre-inspection-survey pigs
for
Electromagnetic inspection: wall loss and flaw location in oil country tubular goods
Heat Resistant Materials. Proceedings of 1st International Conference, Fontana, Wisconsin (United States), 23-26 Sep. 1991. pp. 461-468. Edited by K. Natesan and D.J. Tillack. ASM International (1991) ISBN 0871704293 A new technique for cracking and reforming tube materials, and for detecting the degree of deterioration of cracking tubes used at a petrochemical plant has been developed. A new heat resistant steel is a Ti microalloyed steel with high creep rupture strength and high creep strength. A new type of carburization detector for detecting the carburization of cracking tubes has been developed. The application of this technique in commercial plant improves the reliability of the timing of tube replacement.
49911
method
Materials Evaluation, Vol. 50, No. 4, pp. 502-505 (Apr. 1992) In the inspection of long runs of piping in refineries or chemical plants, a major challenge is determining where to look for problem areas. The magnetic flux technique provides one avenue for the rapid determination of metal loss beneath insulation. The theory and practical examples of the use of the technique are given in this paper. In addition to inspecting installed tubing, the technique is applicable to inspection of used oil well tubing, drill pipe, and wire rope. The technique does not require invasion of the tubing and eliminates the need to shut down production and opening and purging the line as in the wire-line technique.
New heat resistant cast alloys and non-destructive inspection technique in the petrochemical industry
49972
Kirkwood, J.G.; Stanley, R.K.
Total-flux magnetic ferromagnetic tubing
(Nov. 1991) Magneto-acoustic emission (MAE) measurements were made on samples of pipeline steel, under different ac sweep and dc bias field conditions. The MAE activity was found to be highly sensitive to these magnetizing parameters. With increasing amplitude of flux density of the ac sweep field. the MAE rms voltage increases initially and finally tends to saturate: with increasing dc bias field flux density the MAE rms voltage shows a peak, exhibiting maximum MAE activity around the upper steep portion of B-H hysteresis curve. Pulse height distribution analysis of the MAE waveforms indicates that at low fields, near the steep portion of the hysteresis curve, MAE is dominated by 90 domain wall motion while at high fields, nearing saturation,an additional mechanismof domain rotation giving rise to MAE is suggested.
magneto-acoustic
Mackintosh, D.D.; Atherton, D.L.; Porter, P.C.; Teitsma,
Test rigs for magnetic flux leakage inspection tools for pipelines Materials Evaluation, Vol. 50, No. 1, pp. 13- 17 (Jan. 1992) Pipelines carrying oil and gas are normally buried underground and thus inaccessible to many methods of nondestructive evaluations. Inside these plans the environment is relatively harsh and internal in-service inspection
IEEE Transactions on Magnetics, Vol. 28, No. 2, pp. 1003-1007 (Mar. 1992) Magnetoacoustic emission (MAE) in pipeline steel was investigated and
38
N DT Abstracts 47463 Smith, G.; Walters, B. Detecting normally undetectable defects using electro magnetic inspection techniques
mechanisms,or pigs, must be robust. Some pigs use magnetic flux leakage as a test mechanism. This article describes some special test rigs used to develop and test pipeline inspectiontools thus saving time and money. They also offer improved accuracy for corrosion surveys.The test rigs are used to set up extensive engineering studies of the responsesof Magnetic Flux Leakage detectors to defects while simulating the pigs’motion through pipelines. 48501
Petroleum Industry Inspection Technology, Houston, Texas (United States), 20-22 Jun. 1989. pp. 110-l 14. ASNT (1989) During a routine Electra magnetic Inspection (EMI) of tubing string we discovered that the inspection unit was not detecting certain flaws. D.J. Quality Control, in concert with Scan Systems Inc. began a project to identify and provide workable solutions to the problem. The solution included designing new detectors and a frequency filter adaptable to our existing equipment. Inspection procedures were changed in an effort to locate potential problems and prevent a future occurrence. We do not feel this frequency filter is neededall the time and should only be used when it is determined the EMI unit is not detecting known flaws.
Stanley, R.K.
Comments on the internal conductor (threader bar) technique in magnetic particle inspection Materials Evaluation, Vol. 50, No. 1, pp. 18-24 (Jan. 1992) Experimental work on different forms of magnetization (direct current, half-wave rectified alternating current and full-wave rectified alternating current) in Magnetic Particle Inspection, is reported under everyday conditions. Specifications governing the threader bar (internal conductor) technique for magnetic particle inspection are examined. Two theories are outlined which aim to explain misconceptions concerning conductor off-centering. Methods of measuring induced flux density are also discussed. 48505
Shcherbinin, V.E.; Shleenkov, A.S.; Kop’ev, M.A.; Bulychev, O.A.; Rydzevskii, S.I.
47454
Nondestructive inspection of the quality in welded joints in electric welded pipes in the production flow line Soviet Journal of Nondestructive
Wade Edens, C.
Electromagnetic inspection: wall loss and flaw locations in oil country tubular goods International Petroleum Industry Inspection Technology II, Houston Texas (United States), 25-27 Jun. 1991. pp. 105-109. ASNT (1991)
47211
26, No.
12, pp.
Crump, H.M.; Papenfuss. S.
Use of magnetic flux leakage inspection pigs for hard spot detection and repair Materials Performance, Vol. 30, No. 6, pp. 26-28 (Jun. 1991) Areas of elevated hardness(hard spots) in line pipe may crack and fail while in service due to hydrogen stress cracking. This article describes a magnetic flux leakage tool which detectshard spotsreadily due to variation in magnetic behaviour. The hard spot tool passesthrough the pipeline like a conventional cleaning pig. Made in four sections, it is connected by articulated universal joints. The device is also used to facilitate repair by containing the hard spot with full encirclement split sleeve.
Edens, C.W.
Recent innovations in flux leakage drill pipe inspection technology: quality control enhanced Petroleum Industry Inspection Technology, Houston, Texas (United States), 20-22 Jun. 1989. pp. 120-123 ASNT (1989)
46949
Anon.
In line inspection prompts Forties’line replacement Oil & Gas Journal, Vol. 89, No. 24, pp. 37-40 (17 Jun. 1991) An on-line inspection programme, using the magnetic flux-leakage technique, is described for evaluating the condition of sub-sea pipelines in the North Sea used to carry natural gas back to shore. This nondestructive test offers several advantagesover the expensive and disruptive hydrostatic pressure tests used previously. The system described here had to be modified for 32 and 36 inch high-pressurepipes used in the Forties field. The basic inspection sensing apparatus developed to locate, size and subsequently, monitor a particular type of corrosion. The inspection programme is described and some results, especially for deep pitting corrosionare presented.
Drill pipes used in the oil industry can now be tested using electromagnetic inspection (EMI) using solid-state sensingdevices to detect three dimensional flaws. Used correctly this advance in inspection technology will improve quality control of drill pipe inspection. A number of advantagesof the new EM1 devices arc noted. Many of the problems found when using EMI can be overcome with experiencedoperatorsusing the new solid state sensors in conjunlction with advanced signal processing techniques.
41989
Vol.
The current stateof investigationsof the magnetic methodsof inspecting the weld zone of electric welded pipes in the production flow line is examined.
Much electromagnetic inspection (EMI) equipment used in the nondestructiveevaluation of used drill pipe and tubing in the petroleum industry is quite old, up to fifteen years old in some cases.The equipment lacks sensitivity to and resolution of three dimensional flaws. Recent up to date advances in EMI systems are described which use sophisticated semiconductorsensorsto overcolme difficulties in flaw detection including wall loss location. These sensorsare available either in new equipment or as a retrofit for existing pipe inspectionequipment. This usaof semiconductors as flux sensorscan offer greater quality control of used tubular products, leading to increasedwellhead safety.
47990
Testing,
865-870 (Aug. 1991)
Lutzenburg, T.G.
In service pipeline surveys Petroleum Industry Inspection Technology, Houston, Texas (United States), 20-22 Jun. 1989. pp. 165-169 ASNT (1989)
45751 Atherton, D.L.; Laursen, P. A test rig for dynamic measurements of magnetic flux leakage patterns British Journal of Non-Destructive Testing, Vol. 33, No. 2, pp. 69-73 (Feb. 1991)
Surveys of underground pipelines while they arc in service have been successfully conducted for many years using the magnetic flux leakage (MFL) technique. A variety of MFL survey tools are now commercially available and their survey tools are now commercially available and their design and operation are the basis of this article. The three major elefnents of such tools namely the drive section, the transducer section and the instrument section housing the electronic amplifiers and recording systems, are linked by universal joints. The location and orientation of a defect can both be determined using MFL. Flaws such as corrosion, and mechanical and milling defects can also be assessed.
A special test rig for magnetic flux leakage detectors for pipeline monitoring applications is described. It enables detailed maps of defectinduced flux-leakage patternsto be made under dynamic conditions. It uses short ring sectionsof line pipe supportedand driven by an internal wheel. Test detectors arc pressed against the outside of the pipe.. Examples of experimental measurementsare presented.A mechanical device can be used to stress the line-pipe ring to investigate the additional effects of line-pressurestresson detector performance.
47128 Dubov, A.A. Failure mechanism of boiler pipes and the magnetic method of diagnostics of sections with highest damage susceptibility Technical Diagnostics and Nondestructive Testing, Vol. 3, No. 2, pp. 106-10s (1991)
45464
Kahil, J.
Pipe inspection method gives 3D view of OCTG defects World Oil, Vol. 211, No. 1, pp. 87-95 (Jul. 1990) Ferromagnetic pipes, widely used in the oil industry can now bc inspected for small defects using a new technology, called Pipe-Image. which is based on magnetic flux leakage test. It utilizes detector design, digital signal processing and an innovative imaging presentation of inspection results, and is fast, rugged and economical to run. It greatly enhancesthe resolution of the magnetic flux leakage method. High quality signals from smaller sensor permit the detection of smaller (and oblique) defects which previous magnetic flux leakage tests would have overlooked. The method identifies defect type, severity, location and orientation, and hence offer automatic pipe.inspection.
High stressconcentrationsin boiler pipes are the main sourcesof failure. This article describes a ma,gnetic method of nondestructive testing developed to offer early detection of pipe areas suffering from high stress concentrations,characterized by active corrosion, creep and failure factors. The mechanism of failure in these areas is also examined. The inspection method can be used independently or in combination with conventional means to inspect pipes in thermal and nuclear power stations, boilers and many other industrial applications in order to ensure heat exchanger and piping reliability.
39
found to increase linearly with the magnetizing frequency. The rate of increase of MAE rms voltage with frequency was found to depend on the magnitude of the magnetic flux density. The observed MAE waveforms have been analyzed in terms of the frequency dependence of their rms voltage and the muse-height distribution of MAE voltage oulses. With incre&ing magnetizing frequency, the smaller amplitude MAE pulses are replaced by large amplitude pulses, and the total number of MAE pulses also increases. The results are discussed in light of existing models of domain wall motion and magnetoacoustic emission.
Dhar, A.; Clapham, L.; Atherton, D.L.
Effect of sweep and bias field amplitudes on the magnetoacoustic emission IEEE Transactions on Magnetics, Vol. 27, No. 6, pp. 53645366
49520
49976
495 16
Yoshimoto, T.; Takahashi, M.
48522
48521
Bal, C.
Nestleroth, J.B.; Lindsay, B.B.; Davis, R.J.
Papenfuss, S.
International Petroleum Industry Inspection Technology II, Houston Texas (United States), 25-27 Jun. 1991. pp. 14-21. ASNT (1991) The conscientious pipeline operator must monitor many aspects of operational pipeline deterioration. Additionally, some operators must deal with pipelines containing manufacturing defects known as hardspots. A magnetic flux leakage tool readily detects regions of elevated hardness (hardspots) in line pipe.. Hardspots may be evaluated with a hardness tester and gauss meter. Repair of hard spots can be accomplished by pipe replacement or the installation of full encirclement weldover sleeves. By reliable detection of hardspots with flux leakage tool, and the appropriate on-site, post survey verification and repair, hardspot failures can be reduced, if not eliminated.
Pipes&Pipelines International, Vol. 37, No. 3, pp. II-15 (May-Jun. 1992) Misunderstandingscan occur between pipeline operators and inspection operators over the use of intelligent pigs and the preparation necessary before they are used. Possible causes for such misunderstandings are described by detailing all the activities required for a pre-inspection survey. Single pig runs will not necessarily produce conclusive information on pipe-wall surface conditions as the amount and speed of data collected are prodigous. Such pipe-line survey form only part of an overall maintenance programme and it is essential for the contractor to have access to relevant pipeline data so that the pig survey report format is compatible to the maintenance programme.
48508 A.
Dhar, A.; Atherton, D.L.
of
Edens, C. W.
Utilization of magnetic flux leakage inspection pigs for bardspot detection and repair
activities for magnetic-flux intelligent
dependence
installed
International Petroleum Industry Inspection Technology II, Houston Texas (United States), 25-27 Jun. 1991. pp. 9-13. ASNT (1991) Magnetic flux leakage (MFL) for metal-loss defect detection and characterization is the most completely developed and frequently used technology for in-line inspection (IL]) of natural gas pipelines. The focus of this paper is on the results of finite element modelling of the magnetic flux leakage phenomena. Signal features will be correlated against defect geometry to illustrate defect-signal relationships. For example, defect length can be estimated from peak amplitude location of the normal field. The effects of defect width, depth and shape on the estimation of length will be presented. Though these modelling results will provide an upper level of performance of MFL inspection technology, the general capabilities can be addressed.
Pipeline Pigging Technology, 2nd Edition, 1992. Edited by J.N.H. Tiratsoo. pp. 303-324. Gulf Publishing Company (1992) The advent of high-resolution magnetic-based on-line inspection and monitoring equipment now allows operators to thoroughly assess the integrity of a pipehne. This equipment can find all significant defects in the line, and it is then the operators’ responsibility to determine whether these defects require repair. The significance of many pipeline defects can be assessed using proven simple analytical methods. These methods can be applied to assessdefects detected in- service, or to plan inspection schedules for corroding pipelines. This paper describes the variety of pipe-wall defects that can be detected during pigging, and summarizes their assessment methods. The incorporation of these methods into condition-monitoring plans is discussed, and finally an overall defect assessment methodology is presented.
Magnetizing frequency emission in pipeline steel
of
Magnetic flux leakage signal analysis for metal-loss defect characterization
The assessment of pipeline defects during pigging operations
49717
inspection
Materials Evaluation, Vol. 50, No. 4, pp. 476-480 (Atp. 1992) Tradition techniques for inspecting oil country tubular goods (OCTG), such as electromagnetic inspection, are often inefficient at locating service-induced flaws and wail loss in drill pipe and tubing. The approach described in this article aims to overcome these difficulties using a solid-state, small-area detector. The increased sensitivity to flaws of devices provides a better opportunity to locate three dimensional defects. They are highly recommended to replace the less- efficient search coil and gamma ray tools currently used in electromagnetic inspection systems.The use of semiconductors as flux sensors lead to better quality control of used tubular products.
Hopkins, P.
Pre-inspection-survey pigs
for
Electromagnetic inspection: wall loss and flaw location in oil country tubular goods
Heat Resistant Materials. Proceedings of 1st International Conference, Fontana, Wisconsin (United States), 23-26 Sep. 1991. pp. 461-468. Edited by K. Natesan and D.J. Tillack. ASM International (1991) ISBN 0871704293 A new technique for cracking and reforming tube materials, and for detecting the degree of deterioration of cracking tubes used at a petrochemical plant has been developed. A new heat resistant steel is a Ti microalloyed steel with high creep rupture strength and high creep strength. A new type of carburization detector for detecting the carburization of cracking tubes has been developed. The application of this technique in commercial plant improves the reliability of the timing of tube replacement.
49911
method
Materials Evaluation, Vol. 50, No. 4, pp. 502-505 (Apr. 1992) In the inspection of long runs of piping in refineries or chemical plants, a major challenge is determining where to look for problem areas. The magnetic flux technique provides one avenue for the rapid determination of metal loss beneath insulation. The theory and practical examples of the use of the technique are given in this paper. In addition to inspecting installed tubing, the technique is applicable to inspection of used oil well tubing, drill pipe, and wire rope. The technique does not require invasion of the tubing and eliminates the need to shut down production and opening and purging the line as in the wire-line technique.
New heat resistant cast alloys and non-destructive inspection technique in the petrochemical industry
49972
Kirkwood, J.G.; Stanley, R.K.
Total-flux magnetic ferromagnetic tubing
(Nov. 1991) Magneto-acoustic emission (MAE) measurements were made on samples of pipeline steel, under different ac sweep and dc bias field conditions. The MAE activity was found to be highly sensitive to these magnetizing parameters. With increasing amplitude of flux density of the ac sweep field. the MAE rms voltage increases initially and finally tends to saturate: with increasing dc bias field flux density the MAE rms voltage shows a peak, exhibiting maximum MAE activity around the upper steep portion of B-H hysteresis curve. Pulse height distribution analysis of the MAE waveforms indicates that at low fields, near the steep portion of the hysteresis curve, MAE is dominated by 90 domain wall motion while at high fields, nearing saturation,an additional mechanismof domain rotation giving rise to MAE is suggested.
magneto-acoustic
Mackintosh, D.D.; Atherton, D.L.; Porter, P.C.; Teitsma,
Test rigs for magnetic flux leakage inspection tools for pipelines Materials Evaluation, Vol. 50, No. 1, pp. 13- 17 (Jan. 1992) Pipelines carrying oil and gas are normally buried underground and thus inaccessible to many methods of nondestructive evaluations. Inside these plans the environment is relatively harsh and internal in-service inspection
IEEE Transactions on Magnetics, Vol. 28, No. 2, pp. 1003-1007 (Mar. 1992) Magnetoacoustic emission (MAE) in pipeline steel was investigated and
38
N DT Abstracts 47463 Smith, G.; Walters, B. Detecting normally undetectable defects using electro magnetic inspection techniques
mechanisms,or pigs, must be robust. Some pigs use magnetic flux leakage as a test mechanism. This article describes some special test rigs used to develop and test pipeline inspectiontools thus saving time and money. They also offer improved accuracy for corrosion surveys.The test rigs are used to set up extensive engineering studies of the responsesof Magnetic Flux Leakage detectors to defects while simulating the pigs’motion through pipelines. 48501
Petroleum Industry Inspection Technology, Houston, Texas (United States), 20-22 Jun. 1989. pp. 110-l 14. ASNT (1989) During a routine Electra magnetic Inspection (EMI) of tubing string we discovered that the inspection unit was not detecting certain flaws. D.J. Quality Control, in concert with Scan Systems Inc. began a project to identify and provide workable solutions to the problem. The solution included designing new detectors and a frequency filter adaptable to our existing equipment. Inspection procedures were changed in an effort to locate potential problems and prevent a future occurrence. We do not feel this frequency filter is neededall the time and should only be used when it is determined the EMI unit is not detecting known flaws.
Stanley, R.K.
Comments on the internal conductor (threader bar) technique in magnetic particle inspection Materials Evaluation, Vol. 50, No. 1, pp. 18-24 (Jan. 1992) Experimental work on different forms of magnetization (direct current, half-wave rectified alternating current and full-wave rectified alternating current) in Magnetic Particle Inspection, is reported under everyday conditions. Specifications governing the threader bar (internal conductor) technique for magnetic particle inspection are examined. Two theories are outlined which aim to explain misconceptions concerning conductor off-centering. Methods of measuring induced flux density are also discussed. 48505
Shcherbinin, V.E.; Shleenkov, A.S.; Kop’ev, M.A.; Bulychev, O.A.; Rydzevskii, S.I.
47454
Nondestructive inspection of the quality in welded joints in electric welded pipes in the production flow line Soviet Journal of Nondestructive
Wade Edens, C.
Electromagnetic inspection: wall loss and flaw locations in oil country tubular goods International Petroleum Industry Inspection Technology II, Houston Texas (United States), 25-27 Jun. 1991. pp. 105-109. ASNT (1991)
47211
26, No.
12, pp.
Crump, H.M.; Papenfuss. S.
Use of magnetic flux leakage inspection pigs for hard spot detection and repair Materials Performance, Vol. 30, No. 6, pp. 26-28 (Jun. 1991) Areas of elevated hardness(hard spots) in line pipe may crack and fail while in service due to hydrogen stress cracking. This article describes a magnetic flux leakage tool which detectshard spotsreadily due to variation in magnetic behaviour. The hard spot tool passesthrough the pipeline like a conventional cleaning pig. Made in four sections, it is connected by articulated universal joints. The device is also used to facilitate repair by containing the hard spot with full encirclement split sleeve.
Edens, C.W.
Recent innovations in flux leakage drill pipe inspection technology: quality control enhanced Petroleum Industry Inspection Technology, Houston, Texas (United States), 20-22 Jun. 1989. pp. 120-123 ASNT (1989)
46949
Anon.
In line inspection prompts Forties’line replacement Oil & Gas Journal, Vol. 89, No. 24, pp. 37-40 (17 Jun. 1991) An on-line inspection programme, using the magnetic flux-leakage technique, is described for evaluating the condition of sub-sea pipelines in the North Sea used to carry natural gas back to shore. This nondestructive test offers several advantagesover the expensive and disruptive hydrostatic pressure tests used previously. The system described here had to be modified for 32 and 36 inch high-pressurepipes used in the Forties field. The basic inspection sensing apparatus developed to locate, size and subsequently, monitor a particular type of corrosion. The inspection programme is described and some results, especially for deep pitting corrosionare presented.
Drill pipes used in the oil industry can now be tested using electromagnetic inspection (EMI) using solid-state sensingdevices to detect three dimensional flaws. Used correctly this advance in inspection technology will improve quality control of drill pipe inspection. A number of advantagesof the new EM1 devices arc noted. Many of the problems found when using EMI can be overcome with experiencedoperatorsusing the new solid state sensors in conjunlction with advanced signal processing techniques.
41989
Vol.
The current stateof investigationsof the magnetic methodsof inspecting the weld zone of electric welded pipes in the production flow line is examined.
Much electromagnetic inspection (EMI) equipment used in the nondestructiveevaluation of used drill pipe and tubing in the petroleum industry is quite old, up to fifteen years old in some cases.The equipment lacks sensitivity to and resolution of three dimensional flaws. Recent up to date advances in EMI systems are described which use sophisticated semiconductorsensorsto overcolme difficulties in flaw detection including wall loss location. These sensorsare available either in new equipment or as a retrofit for existing pipe inspectionequipment. This usaof semiconductors as flux sensorscan offer greater quality control of used tubular products, leading to increasedwellhead safety.
47990
Testing,
865-870 (Aug. 1991)
Lutzenburg, T.G.
In service pipeline surveys Petroleum Industry Inspection Technology, Houston, Texas (United States), 20-22 Jun. 1989. pp. 165-169 ASNT (1989)
45751 Atherton, D.L.; Laursen, P. A test rig for dynamic measurements of magnetic flux leakage patterns British Journal of Non-Destructive Testing, Vol. 33, No. 2, pp. 69-73 (Feb. 1991)
Surveys of underground pipelines while they arc in service have been successfully conducted for many years using the magnetic flux leakage (MFL) technique. A variety of MFL survey tools are now commercially available and their survey tools are now commercially available and their design and operation are the basis of this article. The three major elefnents of such tools namely the drive section, the transducer section and the instrument section housing the electronic amplifiers and recording systems, are linked by universal joints. The location and orientation of a defect can both be determined using MFL. Flaws such as corrosion, and mechanical and milling defects can also be assessed.
A special test rig for magnetic flux leakage detectors for pipeline monitoring applications is described. It enables detailed maps of defectinduced flux-leakage patternsto be made under dynamic conditions. It uses short ring sectionsof line pipe supportedand driven by an internal wheel. Test detectors arc pressed against the outside of the pipe.. Examples of experimental measurementsare presented.A mechanical device can be used to stress the line-pipe ring to investigate the additional effects of line-pressurestresson detector performance.
47128 Dubov, A.A. Failure mechanism of boiler pipes and the magnetic method of diagnostics of sections with highest damage susceptibility Technical Diagnostics and Nondestructive Testing, Vol. 3, No. 2, pp. 106-10s (1991)
45464
Kahil, J.
Pipe inspection method gives 3D view of OCTG defects World Oil, Vol. 211, No. 1, pp. 87-95 (Jul. 1990) Ferromagnetic pipes, widely used in the oil industry can now bc inspected for small defects using a new technology, called Pipe-Image. which is based on magnetic flux leakage test. It utilizes detector design, digital signal processing and an innovative imaging presentation of inspection results, and is fast, rugged and economical to run. It greatly enhancesthe resolution of the magnetic flux leakage method. High quality signals from smaller sensor permit the detection of smaller (and oblique) defects which previous magnetic flux leakage tests would have overlooked. The method identifies defect type, severity, location and orientation, and hence offer automatic pipe.inspection.
High stressconcentrationsin boiler pipes are the main sourcesof failure. This article describes a ma,gnetic method of nondestructive testing developed to offer early detection of pipe areas suffering from high stress concentrations,characterized by active corrosion, creep and failure factors. The mechanism of failure in these areas is also examined. The inspection method can be used independently or in combination with conventional means to inspect pipes in thermal and nuclear power stations, boilers and many other industrial applications in order to ensure heat exchanger and piping reliability.
39