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Nondestructive measurement of magnetic permeability
N DT Abstracts 57256 Stanley, R.K. Simple explanation of the theory of the total magnetic flux method for the measurement of ferromagnetic cross sections Materials Evaluation, Vol. 53, No. 1, pp. 72-75 (Jan. 1995)
55784 Schmidt, J.T. Magnetic flux leakage inspection of pipelines - an operator’s viewpoint Materials Performance, Vol. 33, No.7, pp. 53-57 (Jul. 1994)
We have outlined the total magnetic flux (TMF) method for the inspection of elongated ferromagnetic product. Because the method detects wall loss in ferromagnetic steel pans, it represents yet another technique for rapid volumetric scanning of such parts.
The use of magnetic flux leakage (MFL) technology for in-line, nondestructive evaluation of natural gas and other pipelines is a competent, cost-effective component in an efficient operation system. MFL provides a comprehensive analysis of metal loss defects, as well as other anomaliesthat could have a detrimental effect on the pipeline’s operation if not discovered and remediated in a timely manner. This article describes an operator’s viewpoint as to the benefits of including this technology in a pipeline quality assurance and integrity program.
56796
Negley, M.; Govindaraju, M.R.; Jiles, D.C.
Neural network prediction of creep damage based on magnetic properties in power plant piping Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), l-6 Aug. 1993. Vol. 13B, pp. 18 17- 1824. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1994) ISBN O-306-4473 l-2 The present investigation explored the use of neural networks to predict
55348
Wade Edens, C.
Coiled tubing: early warning system to detect flaws in flat sheet prior to rolling and welding Materials Evaluation, Vol. 52, No. 5, pp. 582-584 (May 1994) Through experimentation and dynamic evaluation of skelp at a coiled tubing mill, the use of leakage flux solid state sensing devices shows clearly that the requirement for nondestructively testing skelp can be met.
the extent of creep damage. The neural networks were trained with magnetic measurement data collected on welds in high pressure piping in a steam power plant. Results from the investigation indicated that coercivity (Hc), remanence (Br) and their energy product (Hc*Br) were good indicators of creep damage.
54764
Pa&gin,
A.I.; Yakovleva, N.V.
Magnetic and eddy-current methods Russian Journal of Nondestructive Testing, Vol. 29, No. 6, pp. 470-475 (Feb. 1994) We studied experimentally the influence of the magnetizing field strength on the topography of the component of the field of a defect that is tangential to the surface of the product. Investigations with models of defects and with defective specimens of hot-roiled pipes showed that in weak magnetizing fields the field of an inclined defect is analogous in topography to the field of a defect situated normally to the surface of the product, in strong fields there is some asymmetry of the field manifesting itself in the appearance of a negative extremum near the acute angle of the defect. The article suggests a mechanism of formation of the tield of an inclined defect taking into account the influence of the nonlinear dependence of the magnetic properties of the material of the product on the magnetizing field.
56310 Stanley, R.K.; Papadi,mitriou, S. NDE inspection of used coileld tubing
ASNT 1994 Fall Conference and Quality Testing Show, Atlanta, Georgia (United States), 19-23 Sep. 1994. pp. 126-129. ASNT (1994) ISBN I- 57117-002-2 Coiled tubing (CT) is made from - 3000 ft steel strips, welded to length (15,tXG20,000 ft) and ERWd to form pipe. Tensile strengths to 100,000 PSI are possible. Line pipe and tapered string applications are being explored. There are presently no Imandatory NDT requirements on new or used CT, nor any downgrade criteria. NDT is generally MFL for the strip, RT, MT of the 45 deg butt weld, and ET for the formed tube, which may contain ID flash. For used CT, UT and MFL have been tried, and computer models predict when “perfect” tubes will fail by passage over the rig gooseneck. In this paper a magnetic method is outlined.
54554
Kaminski, D.A.; Jiles, D.; Biner, S.B.; Sahlik, M.J.
Stress detection in steels through variations in magnetic properties Review of Progress in Quantitative Nondestructive Evaluation, La Jolla, California (United States), 19-24 Jul. 1992. Vol. 12B, pp. 183 l- I838 Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1993) ISBN 0.306-44483-6
56308 Wincheski, B.; Fultorr, J.; Nath, S.; Simpson, J.; Namkung, M.
Detection of cracks at welds in steel tubing using flux focusing electromagnetic probe ASNT 1994 Fall Conference and Quality Testing Show, Atlanta, Georgia (United States), 19-23 Sep. 1994. pp. 105-107. ASNT (1994) ISBN l- 57117-002-2
Some success has been achieved in recent years in the quantitative measurement of stress along a single axis coaxial with applied magnetic field. This paper reports on subsequent work aimed at the evaluation of the stress in two dimensions. This is clearly a problem of direct relevance to the estimation of stress in the surface of a pipeline.
The Flux Focusing Electromagnetic Flaw Detector, has been adapted for use in testing steel tubing for longitudinal fatigue cracks. The modified design allows for the probe to be placed axisymmetrically into the tubing, inducing eddy currents in the tube wall. The magnetic flux of the primary coil is focused through the use of ferromagnetic material so that in the absence of fatigue damage there will be not flux linkage with the pickup coil. The presence of a longitudinal fatigue crack will cause the eddy currents induced in the tube wall to flow around the flaw and directly under the pickup coil. The use of the: flux focusing electromagnetic probe is especially suited for the detection of flaws originating at or near tube welds. The probe is shown to discriminate against signals due solely to the weld joint so that flaw signals are not hidden in the background in these locations. Experimental and finite element modeling results are presented for the flaw detection capabilities of the probe in stainless steel tubes.
54549
Hayford, D.T.; Kechter, G.E.; Davis, R.J.; McCanney,
T.O.
Nondestructive measurement of magnetic permeability Review of Progress in Quantitative Nondestructive Evaluation, La Jolla, California (United States), 19-24 Jul. 1992. Vol. 12B, pp. 1871-I 878 Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1993) ISBN 0.306-44483-6 A nondestructive method of measuring the permeability of ferromagnetic plates has been developed using an exact solution for the magnetic field transmitted through the plate at low frequencies. Using this method, the permeability of X52 pipeline steel was measured as a function of the magnetization level in the steel. Both these measurements and eddy current measurements of skin depth showed that the permeability was still quite high even though the incremental permeability was essentially one.
56307 Jansen, HJ.M.; van de Camp, P.B.J.; Geerdink, M. Magnetisation as a key paralmeter of magnetic flux leakage pigs for pipeline inspection Insight, Vol. 36, No. 9, pp. 6’72-677 (Sep. 1994) Experimental and modelling studies have been carried out on the error
54546 Nestelroth, J.B.; Davis, R.J. The effects of magnetizer velocity on magnetic flux leakage signals Review of Progress in Quantitative Nondestructive Evaluation, La Jolla, California (United States), 19-24 Jul. 1992. Vol. 12B, pp. 1891-1898 Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1993) ISBN 0.306-44483-6
sources that can influence the reliability of an MFL inspection. It has been found that a number of significant error contributions can be minim&d by a proper design of the magnetising system and when the pipe wall is sufficiently magnetised. On the basis of these Endings, criteria are being developed for pipe wall magnetisation as a function of pipe wall thickness. This “magnetisation operating window” will depend on the design of the magnetic circuit in the pig, whereby there will be a trade-off between pig flexibility and magnetisation capabilities. Implementation of the developed criteria within the MFL pigging services should lead to an increased reliability and sensitivity of an MFL pipeline inspection.
In many magnetic flux leakage applications, the nondestructive inspection constraints suggest the use of high inspection velocities. However, high inspection velocities can compromise the ability to detect and characterize defects. This paper presents the application and results of axis-symmetric finite element modeling for the examination of the effects of
35
55784 Schmidt, J.T. Magnetic flux leakage inspection of pipelines - an operator’s viewpoint Materials Performance, Vol. 33, No.7, pp. 53-57 (Jul. 1994)
We have outlined the total magnetic flux (TMF) method for the inspection of elongated ferromagnetic product. Because the method detects wall loss in ferromagnetic steel pans, it represents yet another technique for rapid volumetric scanning of such parts.
The use of magnetic flux leakage (MFL) technology for in-line, nondestructive evaluation of natural gas and other pipelines is a competent, cost-effective component in an efficient operation system. MFL provides a comprehensive analysis of metal loss defects, as well as other anomaliesthat could have a detrimental effect on the pipeline’s operation if not discovered and remediated in a timely manner. This article describes an operator’s viewpoint as to the benefits of including this technology in a pipeline quality assurance and integrity program.
56796
Negley, M.; Govindaraju, M.R.; Jiles, D.C.
Neural network prediction of creep damage based on magnetic properties in power plant piping Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), l-6 Aug. 1993. Vol. 13B, pp. 18 17- 1824. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1994) ISBN O-306-4473 l-2 The present investigation explored the use of neural networks to predict
55348
Wade Edens, C.
Coiled tubing: early warning system to detect flaws in flat sheet prior to rolling and welding Materials Evaluation, Vol. 52, No. 5, pp. 582-584 (May 1994) Through experimentation and dynamic evaluation of skelp at a coiled tubing mill, the use of leakage flux solid state sensing devices shows clearly that the requirement for nondestructively testing skelp can be met.
the extent of creep damage. The neural networks were trained with magnetic measurement data collected on welds in high pressure piping in a steam power plant. Results from the investigation indicated that coercivity (Hc), remanence (Br) and their energy product (Hc*Br) were good indicators of creep damage.
54764
Pa&gin,
A.I.; Yakovleva, N.V.
Magnetic and eddy-current methods Russian Journal of Nondestructive Testing, Vol. 29, No. 6, pp. 470-475 (Feb. 1994) We studied experimentally the influence of the magnetizing field strength on the topography of the component of the field of a defect that is tangential to the surface of the product. Investigations with models of defects and with defective specimens of hot-roiled pipes showed that in weak magnetizing fields the field of an inclined defect is analogous in topography to the field of a defect situated normally to the surface of the product, in strong fields there is some asymmetry of the field manifesting itself in the appearance of a negative extremum near the acute angle of the defect. The article suggests a mechanism of formation of the tield of an inclined defect taking into account the influence of the nonlinear dependence of the magnetic properties of the material of the product on the magnetizing field.
56310 Stanley, R.K.; Papadi,mitriou, S. NDE inspection of used coileld tubing
ASNT 1994 Fall Conference and Quality Testing Show, Atlanta, Georgia (United States), 19-23 Sep. 1994. pp. 126-129. ASNT (1994) ISBN I- 57117-002-2 Coiled tubing (CT) is made from - 3000 ft steel strips, welded to length (15,tXG20,000 ft) and ERWd to form pipe. Tensile strengths to 100,000 PSI are possible. Line pipe and tapered string applications are being explored. There are presently no Imandatory NDT requirements on new or used CT, nor any downgrade criteria. NDT is generally MFL for the strip, RT, MT of the 45 deg butt weld, and ET for the formed tube, which may contain ID flash. For used CT, UT and MFL have been tried, and computer models predict when “perfect” tubes will fail by passage over the rig gooseneck. In this paper a magnetic method is outlined.
54554
Kaminski, D.A.; Jiles, D.; Biner, S.B.; Sahlik, M.J.
Stress detection in steels through variations in magnetic properties Review of Progress in Quantitative Nondestructive Evaluation, La Jolla, California (United States), 19-24 Jul. 1992. Vol. 12B, pp. 183 l- I838 Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1993) ISBN 0.306-44483-6
56308 Wincheski, B.; Fultorr, J.; Nath, S.; Simpson, J.; Namkung, M.
Detection of cracks at welds in steel tubing using flux focusing electromagnetic probe ASNT 1994 Fall Conference and Quality Testing Show, Atlanta, Georgia (United States), 19-23 Sep. 1994. pp. 105-107. ASNT (1994) ISBN l- 57117-002-2
Some success has been achieved in recent years in the quantitative measurement of stress along a single axis coaxial with applied magnetic field. This paper reports on subsequent work aimed at the evaluation of the stress in two dimensions. This is clearly a problem of direct relevance to the estimation of stress in the surface of a pipeline.
The Flux Focusing Electromagnetic Flaw Detector, has been adapted for use in testing steel tubing for longitudinal fatigue cracks. The modified design allows for the probe to be placed axisymmetrically into the tubing, inducing eddy currents in the tube wall. The magnetic flux of the primary coil is focused through the use of ferromagnetic material so that in the absence of fatigue damage there will be not flux linkage with the pickup coil. The presence of a longitudinal fatigue crack will cause the eddy currents induced in the tube wall to flow around the flaw and directly under the pickup coil. The use of the: flux focusing electromagnetic probe is especially suited for the detection of flaws originating at or near tube welds. The probe is shown to discriminate against signals due solely to the weld joint so that flaw signals are not hidden in the background in these locations. Experimental and finite element modeling results are presented for the flaw detection capabilities of the probe in stainless steel tubes.
54549
Hayford, D.T.; Kechter, G.E.; Davis, R.J.; McCanney,
T.O.
Nondestructive measurement of magnetic permeability Review of Progress in Quantitative Nondestructive Evaluation, La Jolla, California (United States), 19-24 Jul. 1992. Vol. 12B, pp. 1871-I 878 Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1993) ISBN 0.306-44483-6 A nondestructive method of measuring the permeability of ferromagnetic plates has been developed using an exact solution for the magnetic field transmitted through the plate at low frequencies. Using this method, the permeability of X52 pipeline steel was measured as a function of the magnetization level in the steel. Both these measurements and eddy current measurements of skin depth showed that the permeability was still quite high even though the incremental permeability was essentially one.
56307 Jansen, HJ.M.; van de Camp, P.B.J.; Geerdink, M. Magnetisation as a key paralmeter of magnetic flux leakage pigs for pipeline inspection Insight, Vol. 36, No. 9, pp. 6’72-677 (Sep. 1994) Experimental and modelling studies have been carried out on the error
54546 Nestelroth, J.B.; Davis, R.J. The effects of magnetizer velocity on magnetic flux leakage signals Review of Progress in Quantitative Nondestructive Evaluation, La Jolla, California (United States), 19-24 Jul. 1992. Vol. 12B, pp. 1891-1898 Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1993) ISBN 0.306-44483-6
sources that can influence the reliability of an MFL inspection. It has been found that a number of significant error contributions can be minim&d by a proper design of the magnetising system and when the pipe wall is sufficiently magnetised. On the basis of these Endings, criteria are being developed for pipe wall magnetisation as a function of pipe wall thickness. This “magnetisation operating window” will depend on the design of the magnetic circuit in the pig, whereby there will be a trade-off between pig flexibility and magnetisation capabilities. Implementation of the developed criteria within the MFL pigging services should lead to an increased reliability and sensitivity of an MFL pipeline inspection.
In many magnetic flux leakage applications, the nondestructive inspection constraints suggest the use of high inspection velocities. However, high inspection velocities can compromise the ability to detect and characterize defects. This paper presents the application and results of axis-symmetric finite element modeling for the examination of the effects of
35