Metal loss characterization in 55-gallon drum steel by the magnetic flux leakage method

A technique, using Magnetic Flux Leakage (MFL), has been developed for imaging corrosion damage in real-time on the inner surface of sealed 55-gallon drums. An experimental study and theoretical background are presented showing the sensitivity of an MFL technique for detecting and imaging both general and localized corrosion on the inner surface of sealed 55-gallon drums, inspected from the outer surface. Measurements resulting from studies on natural corrosion and machined defects in 55-gallon drum steel will be discussed. Image processing techniques applied to scan data show metal loss in 2-D gray scale images. This work suggests an approach to designing a real-time, full-coverage, 55-gallon drum inspection system to characterize drum wall thickness for comparison over time to determine corrosion rate