THE LASER ABLATION DESORPTION PROCESS USED AS A NEW METHOD FOR CLEANING TREATMENT OF LOW-CARBON STEEL SHEETS/

The properties of electroplated or galvanized coatings deposited on lo w carbon steel sheets depend especially on the chemical state of the s urface. The adhesion between the two materials is affected by residual compounds on the steel surface arising from industrial preparation pr ocesses. In particular, residual rolling oil used as a lubricant to im prove the cold-rolling step of the steel is almost degraded during the following annealing step. Nevertheless, some residual carbonaceous co mpounds remain in a low proportion on the surface of the steel sheets before the later surface treatment. In order to improve the cleanlines s of the surface of steel sheets we performed a method based on the la ser ablation/desorption process. The experiments are realized on steel sheet samples from the cold-rolling and the annealing stages. By adju sting the laser wavelength and the laser power density (irradiance) it is possible to remove about 90% of the residual carbonaceous pollutan ts and 75% of the iron fines (particulates remaining on the surface of the steel after rolling). (C) 1998 Published by Elsevier Science S.A.