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Capacitor discharge magnetization of oil country tubular goods
obtained for stray flux which are characteristic for the various positions of the magnetic field sensors along the surface of the body or body section are stored as reference values. In a second measuring phase in which the body may rotate the reference values allocated to the various positions are subtracted from the stray flux values measured at these positions. The differences are then compared with predetermined threshold values. The first measuring phase is preferably carried out on a fault-free sample but the sample may contain faults since the values measured on the two phases are relative values. 37406
NDT Technologies, Inc.,
Method and apparatus for magnetically inspecting elongated objects for structural defects U.S. Patent No. 4,659,991 (21 Apr. 1987) A magnetic inspection device for nondestructively detecting loss in metallic cross section and localized discontinuities in elongated objects, such as wire cables, rods, pipes, and the like has been developed. 37405
Theiner, W.A.; Deimel, P.
Non-Destructive testing of welds with the 3MA-analyzer Nuclear Engineering and Design, Vol. 102, No. 3, pp. 257-264 (Jul. 1987) For the microstructure and stress determination in the near surface region (< l mm) micromagnetic non-destructive methods can be used. This contribution gives an actual survey about the possibilities of determining non-destructively hardness and residual stress values in the weld region. 37169
Stanley, R.K.
Use of inductive ammeters to ensure saturation of tubular magnetic materials using the internal conductor method Materials Evaluation, Vol. 45, No. 6, pp. 594-598 (Jun. 1987) A previous article outlined the use of inductive ammeters to check both the measurable parameters of a current pulse from a capacitor discharge (CD) system and the effectiveness of the magnetic field intensity (H) from such a pulse in magnetizing a ferromagnetic tubular material. The following short article provides proof that the inductive ammeter can be used to construct a specification for magnetization by this method, thereby obviating unscientific specifications according to amperes perinch of pipe outer diameter. 37168
Pro, R.J.
Grinding burn detection during production using magnetic Barkhausen Noise measurements Materials Evaluation, Vol. 45, No. 6, pp. 610, 612 (Jun. 1987) Grinding may adversely affect the mechanical properties of a finished metallic part if performed improperly. The variations in surface hardness. brittleness, and stress that result when grinding burns are present often lead to surface cracking. Uneven surface wear is another problem that may occur in burned parts. Barkhausen noise measurement lets one nondestructively assess the state of stress if the microstructure of a material is controlled or to detect microstructural defects if the state of stress is controlled. This fact has important implications for the detection of grinding burns. 37167
Fujinaka, Y.; Hanasaki, K.; Tsukada, K.
Magnetic inspection of P.W.S. ropes l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 154-161. Taylor Publishing Co., Dallas (1985). A leakage magnetic flux method was used to evaluate the deterioration of Parallel Wire Strand (P.W.S.) suspension cables. A method is developed for estimating the residual strength of a corroded P.W.S. due to loss in the cross section area obtained by inspection records. 37166
Fitzpatrick, G.L.
Imaging near-surface flaws in ferromagnetic materials using magnetooptic detectors l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 186-191. Taylor Publishing Co., Dallas (1985). A new method for direct, instantaneous viewing of near-surface flaws in ferromagnetic materials has been developed. By using special magnetic garnet films (a magneto-optic material), it is possible to make the magnetic fields associated with near-surface flaws visible. Moreover, by properly biasing the magnetic garnet film with an external magnetic field, these images can reproduce the size and shape of the flaws. In many applications the new viewing method can replace conventional magnetic particle or flux leakage inspection techniques. The new viewing method appears to be especially well suited to production line applications where minimal sample preparation and rapid inspection are basic requirements. Because the magnetic garnet film responds to fields associated with eddy currents, the method may be applicable to nonmagnetic conductors. 37165
Lasarev, S.; Shaternikov, V.
Nondestructive testing with scanning electromagnetic fields of changing topology l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 192-199. Taylor Publishing Co., Dallas (1985). The report considers the problem of varying topology of electromagnetic fields in the process of testing. Design principles of eddy current transducers
NDT International February 1989
(ECT) as well as nondestructive testing systems using scanning electromagnetic fields with variable topology are described. 37164
Hiroshima, T.; Hirota, 7".; Hyodo, S.; Furukawa, Y.
A new electromagnetic testing method using compound magnetic field l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 200-207. Taylor Publishing Co., Dallas (1985). In order to detect a three dimensional surface defect on both magnetic and non-magnetic materials, an unique electromagnetic testing method has been developed. 37163
Qi, Z.; Lunyuan, Y.
Near crack in ferromagnetic materials for magnetic NDT l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 216-225. Taylor Publishing Co., Dallas (1985). A mathematical model of magnetic testing is proposed after analysis of the leakage field producing mechanism. A finite element method is applied to solve nonlinear magnetic leakage field problems. Analyses and calculations are made on the distribution of the leakage field near cracks in ferromagnetic materials. The leakage flux caused by artificial cracks was measured by means of a Gaussmeter with a Hall probe. Values calculated using the model correspond to experimental results. 37162
Cheu, Y.F.
Automatic crack detection with computer recognition of magnetic particle indications
vision and pattern
l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 293-300. Taylor Publishing Co., Dallas (1985). Fluorescent Magnetic Particle Inspection (FMPI) is a widely used technology to inspect ferromagnetic parts for surface cracks. FMPI is very effective in making cracks visible, but the ultimate detection of the fluorescent crack indication is dependent on the human inspector. This paper discusses problems and solutions of automating the manual detection operation. An automatic system to detect cracks in connecting rods is also described. 37161
Exton, C.H.
Some recent developments in magnetic particle inspection l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 317-322. Taylor Publishing Co., Dallas (1985). This paper contains a miscellany of experiments and developments aimed at improving both techniques and equipment. 37160
Yamada, H.; Kishimoto, S.; ltoh, M.; Takenaka, Y.
Stress analysis with a magnetic anisotropy sensor and its application llth World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 607-614. Taylor Publishing Co., Dallas (1985). Two types of magnctic anisotropies are known: one is a physical property inherent in a magnetic material and is another to be temporarily generated in a magnetic material by stress, magnetostriction, etc. A magnetic anisotropy sensor (MAS in short) developed by the authors has enabled us to measure magnetic torque curves and hardened depths of magnetic materials. This paper will describe the operation principle of the MAS and present an analytical result on the relationship between magnetic anisotropy patterns obtained with the MAS. It has been clarified theoretically that magnetic anisotropy patterns obtained with the MAS depend upon the directional permeability of materials. 37159
Spierer E.D.
Flux density measurement in ferromagnetic tubular product Electromagnetic Methods of Nondestructive Testing. Edited by William Lord. Nondestructive Testing Monographs and Tracts, Vol. 3, pp. 161- 173. Gordon and Breach Science Publishers (1985). Flux leakage testing of ferromagnetic tubular product for defects requires that the flux density in such product be near 95% of saturation when being tested. If the flux density in the material under test is significantly below saturation, inside-diameter and mid- wall defects will be missed. Until recently there has been no means of determining the value of the flux density in the tubular product or whether this value is maintained during testing in order to validate the test. This paper presents a solution to the problem of continuous determination of the flux density in the material under test. 37158
Moake, G.L.; Stanley, R.K.
Capacitor discharge magnetization of oil country tubular goods Electromagnetic Methods of Nondestructive Testing. Edited by William Lord. Nondestructive Testing Monographs and Tracts, Vol. 3, pp. 151- 160. Gordon and Breach Science Publishers (1985). The circular magnetization of Oil Country Tubular Goods (OCTG) is normally performed by capacitor discharge (CD) along a central conductor which is insulated from the tube being magnetized. The magnetization process is complicated by the induction of an eddy current which flows in a manner which opposes penetration of the magnetizing field. In this article, we outline the development of a CD system which will adequately magnetize a wide range of OCTG, despite the demagnetizing effect of the eddy current. We also discuss the effectiveness of multiple pulsing.
61
NDT Technologies, Inc.,
Method and apparatus for magnetically inspecting elongated objects for structural defects U.S. Patent No. 4,659,991 (21 Apr. 1987) A magnetic inspection device for nondestructively detecting loss in metallic cross section and localized discontinuities in elongated objects, such as wire cables, rods, pipes, and the like has been developed. 37405
Theiner, W.A.; Deimel, P.
Non-Destructive testing of welds with the 3MA-analyzer Nuclear Engineering and Design, Vol. 102, No. 3, pp. 257-264 (Jul. 1987) For the microstructure and stress determination in the near surface region (< l mm) micromagnetic non-destructive methods can be used. This contribution gives an actual survey about the possibilities of determining non-destructively hardness and residual stress values in the weld region. 37169
Stanley, R.K.
Use of inductive ammeters to ensure saturation of tubular magnetic materials using the internal conductor method Materials Evaluation, Vol. 45, No. 6, pp. 594-598 (Jun. 1987) A previous article outlined the use of inductive ammeters to check both the measurable parameters of a current pulse from a capacitor discharge (CD) system and the effectiveness of the magnetic field intensity (H) from such a pulse in magnetizing a ferromagnetic tubular material. The following short article provides proof that the inductive ammeter can be used to construct a specification for magnetization by this method, thereby obviating unscientific specifications according to amperes perinch of pipe outer diameter. 37168
Pro, R.J.
Grinding burn detection during production using magnetic Barkhausen Noise measurements Materials Evaluation, Vol. 45, No. 6, pp. 610, 612 (Jun. 1987) Grinding may adversely affect the mechanical properties of a finished metallic part if performed improperly. The variations in surface hardness. brittleness, and stress that result when grinding burns are present often lead to surface cracking. Uneven surface wear is another problem that may occur in burned parts. Barkhausen noise measurement lets one nondestructively assess the state of stress if the microstructure of a material is controlled or to detect microstructural defects if the state of stress is controlled. This fact has important implications for the detection of grinding burns. 37167
Fujinaka, Y.; Hanasaki, K.; Tsukada, K.
Magnetic inspection of P.W.S. ropes l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 154-161. Taylor Publishing Co., Dallas (1985). A leakage magnetic flux method was used to evaluate the deterioration of Parallel Wire Strand (P.W.S.) suspension cables. A method is developed for estimating the residual strength of a corroded P.W.S. due to loss in the cross section area obtained by inspection records. 37166
Fitzpatrick, G.L.
Imaging near-surface flaws in ferromagnetic materials using magnetooptic detectors l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 186-191. Taylor Publishing Co., Dallas (1985). A new method for direct, instantaneous viewing of near-surface flaws in ferromagnetic materials has been developed. By using special magnetic garnet films (a magneto-optic material), it is possible to make the magnetic fields associated with near-surface flaws visible. Moreover, by properly biasing the magnetic garnet film with an external magnetic field, these images can reproduce the size and shape of the flaws. In many applications the new viewing method can replace conventional magnetic particle or flux leakage inspection techniques. The new viewing method appears to be especially well suited to production line applications where minimal sample preparation and rapid inspection are basic requirements. Because the magnetic garnet film responds to fields associated with eddy currents, the method may be applicable to nonmagnetic conductors. 37165
Lasarev, S.; Shaternikov, V.
Nondestructive testing with scanning electromagnetic fields of changing topology l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 192-199. Taylor Publishing Co., Dallas (1985). The report considers the problem of varying topology of electromagnetic fields in the process of testing. Design principles of eddy current transducers
NDT International February 1989
(ECT) as well as nondestructive testing systems using scanning electromagnetic fields with variable topology are described. 37164
Hiroshima, T.; Hirota, 7".; Hyodo, S.; Furukawa, Y.
A new electromagnetic testing method using compound magnetic field l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 200-207. Taylor Publishing Co., Dallas (1985). In order to detect a three dimensional surface defect on both magnetic and non-magnetic materials, an unique electromagnetic testing method has been developed. 37163
Qi, Z.; Lunyuan, Y.
Near crack in ferromagnetic materials for magnetic NDT l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 216-225. Taylor Publishing Co., Dallas (1985). A mathematical model of magnetic testing is proposed after analysis of the leakage field producing mechanism. A finite element method is applied to solve nonlinear magnetic leakage field problems. Analyses and calculations are made on the distribution of the leakage field near cracks in ferromagnetic materials. The leakage flux caused by artificial cracks was measured by means of a Gaussmeter with a Hall probe. Values calculated using the model correspond to experimental results. 37162
Cheu, Y.F.
Automatic crack detection with computer recognition of magnetic particle indications
vision and pattern
l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 293-300. Taylor Publishing Co., Dallas (1985). Fluorescent Magnetic Particle Inspection (FMPI) is a widely used technology to inspect ferromagnetic parts for surface cracks. FMPI is very effective in making cracks visible, but the ultimate detection of the fluorescent crack indication is dependent on the human inspector. This paper discusses problems and solutions of automating the manual detection operation. An automatic system to detect cracks in connecting rods is also described. 37161
Exton, C.H.
Some recent developments in magnetic particle inspection l l t h World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 317-322. Taylor Publishing Co., Dallas (1985). This paper contains a miscellany of experiments and developments aimed at improving both techniques and equipment. 37160
Yamada, H.; Kishimoto, S.; ltoh, M.; Takenaka, Y.
Stress analysis with a magnetic anisotropy sensor and its application llth World Conference on Nondestructive Testing, Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 607-614. Taylor Publishing Co., Dallas (1985). Two types of magnctic anisotropies are known: one is a physical property inherent in a magnetic material and is another to be temporarily generated in a magnetic material by stress, magnetostriction, etc. A magnetic anisotropy sensor (MAS in short) developed by the authors has enabled us to measure magnetic torque curves and hardened depths of magnetic materials. This paper will describe the operation principle of the MAS and present an analytical result on the relationship between magnetic anisotropy patterns obtained with the MAS. It has been clarified theoretically that magnetic anisotropy patterns obtained with the MAS depend upon the directional permeability of materials. 37159
Spierer E.D.
Flux density measurement in ferromagnetic tubular product Electromagnetic Methods of Nondestructive Testing. Edited by William Lord. Nondestructive Testing Monographs and Tracts, Vol. 3, pp. 161- 173. Gordon and Breach Science Publishers (1985). Flux leakage testing of ferromagnetic tubular product for defects requires that the flux density in such product be near 95% of saturation when being tested. If the flux density in the material under test is significantly below saturation, inside-diameter and mid- wall defects will be missed. Until recently there has been no means of determining the value of the flux density in the tubular product or whether this value is maintained during testing in order to validate the test. This paper presents a solution to the problem of continuous determination of the flux density in the material under test. 37158
Moake, G.L.; Stanley, R.K.
Capacitor discharge magnetization of oil country tubular goods Electromagnetic Methods of Nondestructive Testing. Edited by William Lord. Nondestructive Testing Monographs and Tracts, Vol. 3, pp. 151- 160. Gordon and Breach Science Publishers (1985). The circular magnetization of Oil Country Tubular Goods (OCTG) is normally performed by capacitor discharge (CD) along a central conductor which is insulated from the tube being magnetized. The magnetization process is complicated by the induction of an eddy current which flows in a manner which opposes penetration of the magnetizing field. In this article, we outline the development of a CD system which will adequately magnetize a wide range of OCTG, despite the demagnetizing effect of the eddy current. We also discuss the effectiveness of multiple pulsing.
61