scholarly journals Non-destructive Evaluation Method for Far-side Corrosion Type Flaws in Oil Storage Tank Bottom Floors Using the Magnetic Flux Leakage Technique

2003 ◽  
Vol 46 (2) ◽  
pp. 126-132 ◽  
Author(s):  
Naoya KASAI ◽  
Kazuyoshi SEKINE ◽  
Hiroaki MARUYAMA
Keyword(s):  
Magnetic Flux ◽  
Storage Tank ◽  
Evaluation Method ◽  
Magnetic Flux Leakage ◽  
Oil Storage ◽  
Non Destructive Evaluation ◽  
Oil Storage Tank ◽  
Tank Bottom ◽  
Non Destructive ◽  
Flux Leakage

scholarly journals Study on design and fabrication of a prototype equipment used for corrosion inspection on petrochemical tank bottom by magnetic flux leakage method

2020 ◽  
pp. 280-288
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnets ◽  
Low Cost ◽  
Scanning Speed ◽  
Magnetic Flux Leakage ◽  
Corrosion Pitting ◽  
Tank Bottom ◽  
Hall Sensors ◽  
Non Destructive ◽  
Flux Leakage

Corrosion of the bottom of the petroleum tank may lead to a product leak that could cause a fire or explosion resulting in damage to people and the environment, therefore the test of tank bottom corrosion is necessary to be conducted periodically to prevent the occurrence of the above problems. In non-destructive inspection, the Magnetic Flux Leakage (MFL) method relies on the variation of fluxes caused by defects on the surface of materials to detect corrosion, pitting, or imperfections, which is proved quite effectively with low cost. The project was implemented to develop a prototype of the MFL bottom detection device based on the research results in the world to improve corrosion survey capacity in industrial equipment, as well as to improve the expertise in the Research Team of electronics and automation in the fields of magnetic fields and sensors. As a result, an MFL model using permanent magnets and Hall sensors were fabricated. Survey experiments showed that the machine could detect corrosion defects up to 20% of steel wall thickness in the scanning speed range from 500 mm/s to 1130 mm/s. However, to meet the actual survey needs, the team must continue to improve the device in terms of sensitivity, scanning speed, the ability to operate automatically or semi-automatically, and register for a fire safety inspection.

Practical evaluation of velocity effects on the magnetic flux leakage technique for storage tank inspection

2020 ◽  
Vol 62 (2) ◽  
pp. 73-80
Author(s):  
A L Pullen ◽  
P C Charlton ◽  
N R Pearson ◽  
N J Whitehead
Keyword(s):  
Magnetic Flux ◽  
Storage Tank ◽  
Eddy Currents ◽  
Surface Defects ◽  
Signal Amplitude ◽  
Magnetic Flux Leakage ◽  
Scanning Velocity ◽  
Near Surface ◽  
Practical Evaluation ◽  
Flux Leakage

Magnetic flux leakage (MFL) is a technique commonly used to inspect storage tank floors. This paper describes a practical evaluation of the effect of scanning velocity on defect detection in mild steel plates with thicknesses of 6 mm, 12 mm and 16 mm using a fixed permanent magnetic yoke. Each plate includes four semi-spherical defects ranging from 20% to 80% through-wall thickness. It was found that scanning velocity has a direct effect on defect characterisation due to the distorted magnetic field resulting from induced eddy currents that affect the MFL signal amplitude. This occurs when the inspection velocity is increased and a reduction in the MFL signal amplitudes is observed for far-surface defects. The opposite applies for the top surface, where an increase is seen for near-surface MFL amplitudes when there is insufficient flux saturating the inspection material due to the concentration of induced flux near the top surface. These findings suggest that procedures should be altered to minimise these effects based on inspection requirements. For thicker plates and when far-surface defects are of interest, inspection speeds should be reduced. If only near-surface defects are being considered then increased speeds can be used, provided that the sensor range is sufficient to cope with the increased signal amplitudes so that signal clipping does not become an issue.

2253 Non-destructive Inspection of Corrosion on a Bottom Plate of Oil Storage Tank Based on Electric Potential Method

2005 ◽  
Vol 2005.1 (0) ◽  
pp. 669-670
Author(s):  
Yasunori SHINDO ◽  
Naotake OHTSUKA ◽  
Takatoshi FURUI ◽  
Hiroshi YABE ◽  
Tomoko HIRAYAMA
Keyword(s):  
Electric Potential ◽  
Storage Tank ◽  
Potential Method ◽  
Bottom Plate ◽  
Oil Storage ◽  
Oil Storage Tank ◽  
Non Destructive
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