Surface preparation for shipbuilding using pulsed high-power fibre laser

Surface preparation is an important step prior to welding and coating procedures for building a new ship. The conditions of surface preparation directly determines the quality of welding and painting works, which could further affect the occurrence of corrosion and fouling. Removal of millscales from raw steel plates using abrasive blasting method is often a significant process of surface preparation for shipbuilding work. It is a standard and effective procedure used by worldwide shipyards. But it always causes environmental problems of air pollution and secondary wastes. The increasingly widespread use of lasers on surface treatment provides an option for surface preparation with ecological advantages. In this report, we present the results of removing millscales using a pulsed high-power fibre laser. Laser parameters, including scanning speed, overlap of scanning lines, scanning pattern, repetition rate of laser pulses, laser power and laser pulse energy, are varied and optimized to attain the complete removal of millscales. The mechanism of millscale removal is discussed.