  | MT - Full Paper Not Received |  |
ADVANCES IN MAGNETIC METHODS FOR WALL THICKNESS MEASUREMENT IN FERROMAGNETIC TUBE AND PLATE
Roderic K. Stanley, Quality Tubing Inc.
Houston, Texas, USA
Keywords: Magnetic methods, Non contact measurement, Encircling coil, Magnetic flux leakage sensor, Ferromagnetic tubes
ABSTRACT There is a need for continuous non-contact measurement of wall thickness of ferromagnetic tubes and plates. This need is driven by the desire to rapidly inspect refinery tank floors and piping, and such other oil field tubes as used drill pipe and coiled tubing. Often, measurement is required through insulation, without using radiography. Our earlier work involved the use of an encircling coil for the measurement of the cross-sectional area of drill pipe and tubing, from which the average wall thickness of the tubes is deduced. This paper describes a more recent method in which the coil is broken up into a ring of solid state sensors so that very local losses of wall from erosion, corrosion and eccentricity can be measured. The same sensing system, in strip form, can be used to measure the thickness of steel tank floors. In conjunction with magnetic flux leakage sensors, powerful rapid scans of large volumes of used tubes and plates can be achieved. Areas that are determined to be worn or corroded can then be scanned more slowly with ultrasonic or other methods. Several examples of the use of such wall thickness measurements, in conjunction with MFL measurements, are presented.
| | MT - Full Paper Not Received | |
Publication Source: Trends in NDE Science & Technology; Proceedings of the 14th World Conference on Non-Destructive Testing, New Delhi, 8-13 December 1996.full paper not received
Publisher: Ashgate Publishing Company
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