Effects of Ultra-High Power Continuous Laser Cleaning Process Parameters on the Cleaning Quality of Q355B Steel

Abstract

To investigate the effects of ultra-high power continuous laser cleaning on Q355B steel, an ultra-high power fiber laser was used to clean contaminants such as rust from the surface of Q355B steel. The influence of laser scanning speed and power on the cleaning quality was studied under ultra-high power conditions, and the cleaning efficiency was calculated. Results showed that significant damage was caused to the substrate by the laser when the cleaning speed was below 110 mm/s, and there was still some rust on the surface of the substrate when the speed was above 140 mm/s. At speeds of 120～130 mm/s, the substrate was not damaged, and the rust layer was effectively removed. When the speed was kept constant at 120 mm/s, rust was not completely removed at power levels below 7 500 W, and substrate damage occurred at power levels above 8 500 W. Scanning electron microscopy(SEM) was used to analyze the microstructure of the steel surface before and after cleaning. X-ray diffraction(XRD) and energy-dispersive spectroscopy(EDS) were used to characterize the surface of the workpiece. As the scanning speed increased from 100 mm/s to 150 mm/s and the power increased from 7 000 W to 9 000 W, the iron content on the steel surface after cleaning showed a trend of first increasing and then decreasing, while the oxygen content first decreased and then increased. When the laser power was 8 000 W and the scanning speed was 120 mm/s, the mass fraction of iron on the surface of the cleaned workpiece reached its peak, about 79.25%, and the mass fraction of oxygen reached its valley, about 20.75%. The calculation showed that the highest laser cleaning efficiency could reach 43.2 m2/h. By adjusting the laser power and scanning speed, it was possible to safely and effectively remove surface pollutants from Q355B steel while improving the microhardness of the material surface, thereby achieving ideal and efficient laser cleaning effects.

Keywords

• ultra-high power laser; laser cleaning; rust layer; surface hardness; q355b steel