Laser cleaning of sulfide scale on compressor impeller blade

•The effects of sulfide layers and fluence values on the mechanism of laser cleaning were experimentally established.•The specimen surface with sulfide scale becomes slightly smoother than that before laser cleaning.•The mechanism of laser cleaning the sulfide scale of stainless steel is spallation without oxidization.•It would avoid chemical waste and dust pollution using a fiber laser instead of using nitric acids or sandblasting. Sulfide scale on the surface of a compressor impeller blade can considerably reduce the impeller performance and its service life. To prepare for subsequent remanufacturing, such as plasma spraying, it needs to be removed completely. In the corrosion process on an FV(520)B stainless steel, sulfide scale is divided into two layers because of different outward diffusion rates of Cr, Ni and Fe. In this paper, the cleaning threshold values of the upper and inner layers and the damage threshold value of the substrate were investigated using a pulsed fiber laser. To obtain experimental evidence, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and 3D surface profilometry were employed to investigate the two kinds of sulfide layers on specimens before, during, and after laser cleaning.