Abstract
In order to study whether acoustic emission (AE) can be monitored from atmospheric rust of steel structure, AE monitoring during wet-dry rusting test by five kinds of electrolytes was attempted. It revealed a linear increase of AE counts with rust thickness. AE amplitudes from thicker rusts than 100μm were large enough to be monitored as the in-water longitudinal wave by resonant type AE sensors (450kHz center frequency) mounted on the cylindrical cell wall on the steel plate. The frequencies of these Lamb wave AEs through the steel plate are in the range from 0.3 to 0.5MHz. Mechanical fracture of rust film by four point bending produced AEs with the frequency range 0.6 to 1MHz. AEs were produced due to elastic strains of substrate steel for thicker rust.
