To understand the nanosecond laser derusting process and reveal the derusting mechanism
the surface morphology and roughness of AH32 marine steel after laser derusting under different process parameters was studied. First
a nanosecond-pulse laser was used to clean the rust layer of the sample surface under different process parameters. Then
the surface roughness after cleaning was measured using laser scanning confocal microscopy
the micromorphology was measured by scanning electron microscopy
and an elemental analysis was performed using an energy dispersive spectrometer. Finally
the nanosecond laser derusting mechanism of AH32 marine steel was revealed combined with the experimental results. The experimental results indicated that the cleaned morphology was improved
and that the surface roughness was reduced under stepwise laser cleaning with energy densities of 30.6 and 10.2 J/cm
2
at a scanning speed of 3 000 mm/s. Moreover
under the above cleaning conditions
the micromorphology of the matrix exhibited a micromelting state after laser derusting
in which the spot was smooth and uniform and the edge of the spot was distributed with a dendritic mastoid structure. It can be concluded that the use of a stepwise laser cleaning process can yield a better cleaning effect and higher cleaning efficiency. The derusting mechanism mainly includes hole blasting and melting-vaporization.
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