Electromagnetic testing emt-mft chapter 9b

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PART 3. Application 1.0 Flaw Detection by the Flux Leakage Method. Perhaps the most prevalent use of the flux leakage method is the inspection of ferromagnetic tubular goods, such as gas pipelines, down hole casing, and a variety of other forms of steel piping. In applications in the petroleum industry, the technique is highly developed, but details on inspection devices and methods of data analysis are, for the most part, considered proprietary by the companies that provide inspection services. Still, the techniques currently in use have certain features in common, and these are exemplified by the typical system described below. The device shown in Fig. 8 is an inspection tool for large-diameter pipelines. Magnetization is provided by a large electromagnet fitted with wire brushes to direct magnetic flux from the electromagnet into the pipe wall. To avoid spurious signals from hard spots in the material, the magnetization circuit is designed for maximum flux density in the pipe wall in an attempt to magnetically saturate the material. Charlie Chong/ Fion Zhang
Leakage field sensors are mounted between the pole pieces of the magnet in a circle around the axis of the device to provide, as nearly as possible, full coverage of the pipe wall. In most such tools, the sensors are the inductive coil type, oriented to measure the axial component of the leakage field gradient. Data are usually recorded on magnetic tape as the system is propelled down a section of pipe. After the inspection, the recorded signals are compared with those from calibration standards in an attempt to interpret flaw indications in terms of flaw type and size. Charlie Chong/ Fion Zhang
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Electromagnetic Testing MFLT/ ECT/
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Ship building Charlie Chong/ Fion Z
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Offshore Structures & Appurtenances
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Power Piping Charlie Chong/ Fion Zh
Page 15 and 16: Charlie Chong/ Fion Zhang
Page 17 and 18: Fion Zhang at Shanghai 2015 Februar
Page 19 and 20: Chapter 9B: Magnetic Field Testing
Page 21 and 22: Keywords: Field of magnetic materia
Page 23 and 24: Although it is conceivable that lea
Page 25 and 26: Barkhausen noise: Magnetization (J)
Page 27 and 28: Barkhausen noise A coil of wire wou
Page 29 and 30: A set-up for non-destructive testin
Page 31 and 32: Magnetic Dipole Charlie Chong/ Fion
Page 33 and 34: If a slot is cut in the rod, as ill
Page 35 and 36: 2.2 Experimental Techniques. One of
Page 37 and 38: It is possible to generate a magnet
Page 39 and 40: The flaw leakage field can be detec
Page 41 and 42: Fig. 3 Flux leakage measurement usi
Page 43 and 44: Unlike the inductive coil, which pr
Page 45 and 46: There are, however, many situations
Page 47 and 48: Fig. 5 Dependence of magnetic signa
Page 49 and 50: Fig. 6 Characterization of a ferrit
Page 51 and 52: PART 2. Principles of Magnetic Char
Page 53 and 54: Hysteresis Curves Charlie Chong/ Fi
Page 55 and 56: Nevertheless, the prospect of nonde
Page 57 and 58: Curie temperature Below T c Ferroma
Page 59 and 60: Paramagnetism The magnetic moments
Page 61 and 62: Antiferromagnetism The magnetic mom
Page 63 and 64: Fig. 7 Experimental arrangement for
Page 65: The review articles and conference
Page 69 and 70: In addition to systems for inspecti
Page 71 and 72: The flux leakage method is also fin
Page 73 and 74: Another area in which the flux leak
Page 75 and 76: Finally, the flux leakage method ha
Page 77 and 78: Steel rebars and cables in a large
Page 79 and 80: Fig. 10 Effect of mechanical hardne
Page 81 and 82: Keywords: • For one alloy, AISI 4
Page 83 and 84: Offshore Structures Charlie Chong/
Page 85 and 86: VLCC Charlie Chong/ Fion Zhang
Page 87 and 88: Offshore Structures Charlie Chong/
Page 89 and 90: Pipeline & Piping Charlie Chong/ Fi
Page 91 and 92: Charlie Chong/ Fion Zhang
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Electromagnetic testing emt-mft chapter 9b

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