Surface cleaning of hot-rolled sheet steel by laser ablation of oxide layer using a 100-ns high-repetition frequency pulsed laser

An investigation of laser cleaning of the oxide layers on the surface of the hot-rolled steel sheets was presented both experimentally and theoretically. By using a ∼100-ns pulsed laser, the optimized experimental parameters, such as the scanning speed, spatial overlap between two adjacent scans, and laser power density, were studied to obtain efficient and high-quality cleaning and avoid the formation of new oxide layer due to the heating by the laser. The temperature elevation and ablation depth were simulated and the data agree well with the experimental results. The change of composition of the surface layer, the surface roughness, and hardness due to laser ablation were also measured.