Early corrosion detection in structural carbon steels using electromagnetic sensors

Rumiche, Francisco; Indacochea, J. E.; Wang, M. L.

doi:10.1117/12.660285

Cited by 2 publications

(1 citation statement)

References 14 publications

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“…Because the failure of pipelines carrying different mediums at high pressures and large flows produce significant financial losses, several mentioned physical effects can be used, whereas the MMM method is the most widely utilized. A special area is the aerospace industry, where the magnetic methods can be used in online diagnostics of the turbines of jet engines [51][52][53][54][55]. The approaches are based on the combination of the acoustic and magnetic methods and have been developed and used since the 1980s.…”

Section: Introductionmentioning

confidence: 99%

Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

et al. 2021

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The magnetic field created by technical devices is a source of information. This information could be used in contactless diagnostics and predictive maintenance or for resolving problems along with standard NDT (nondestructive testing) methods, especially if we consider large, slow-speed devices, such as electromotors, transmissions, or generators. Identification of causalities of device failure processes with near magnetic field is one of the suitable NDT methods improving sustainability of systems. The measurements presented in the article were performed with the VEMA 04 fluxgate vector magnetometer with the DC-250 Hz bandwidth and 2 nT sensitivity. Postprocessing of the results was performed in the means of standard methods of discrete Fourier Transform, spectrogram creation and Wavelet Transform. The article presents data gathered during the measurement of a pair of extraction fans with power of 140 kW each and maximum revolutions up to 740 rev/min controlled by frequency converters and a single semi-Kaplan water power plant with 400 kW peak power at 1005 rev/min maximum generator speed. The measurements were performed before and after repairs of one of the ventilators in the ventilation system at 60% and 100% of maximal output power. The rotating magnetic fields of the fan electromotor stator, fan rotor revolutions, rotor slip frequency and ball-bearing frequencies were identified in frequency spectrums in the distance of 700 mm from fan electromotor axis in both cases. During the measurements on the semi-Kaplan turbine, the changes in states of mechanical and electrical components of the machine were monitored in the magnetic fields with increase of the power in the range of 0–95%, before and after phasing to the electrical grid. Standard processing methods, Discrete Fourier Transform, spectrograms and Discrete Wavelet Transform were used. In the spectrograms of the measured magnetic fields, the 1st–4th harmonics of the turbine shaft, generator shaft and also their side frequencies were identified. Significant changes of magnetic fields in time were identified in the area of 60–95% power. With the help of the Wavelet, transform intervals were identified where it is desirable to operate the turbine. The analyses of magnetic fields measurements performed on the power plant were compared with vibro-diagnostic principles.

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Section: Introductionmentioning

confidence: 99%

Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

et al. 2021

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Assessment of the Effect of Microstructure on the Magnetic Behavior of Structural Carbon Steels Using an Electromagnetic Sensor

Rumiche

Indacochea

Wang

2008

J. of Materi Eng and Perform

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The magnetic properties of four carbon steels were evaluated using an electromagnetic sensor and correlated with their microstructures. Their composition, microstructure features (such as ferrite volume fraction, grain size, inclusions, etc), and hardness were compared with their saturated magnetic flux density, retentivity, and coercivity. The four steel rods used in this study were hot-rolled AISI 1010, AISI 1018, AISI 1045, and AISI 1045-high manganese/''stress proof.'' The results show that microstructures have a notable effect on the magnetic properties of the steels. In addition, the effect of variations in cross-section area of the steel rods on the magnetic response was investigated. The steel rods diameters were systematically reduced by machining and then magnetically evaluated. Consistent relationships between metallurgical characteristics of the structural carbon steels and their magnetic properties measured with the electromagnetic sensor were obtained. In addition, the sensor was found to be able to detect changes in magnetic properties due to variations in cross-section area. These results reveal that the electromagnetic sensor has the potential to be used as a reliable nondestructive tool to detect and monitor microstructural and morphological changes occurring during the different stages of steel manufacturing or alterations caused by a degradation mechanism.

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Early corrosion detection in structural carbon steels using electromagnetic sensors

Cited by 2 publications

References 14 publications

Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

Assessment of the Effect of Microstructure on the Magnetic Behavior of Structural Carbon Steels Using an Electromagnetic Sensor

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