Laser cleaning for rust removal on mild steel: An experimental study on surface characteristics

Laser cleaning is a relatively new and promising industrial cleaning method. Despite its potential as an alternative to conventional de-rusting methods, very few studies have been done on rust removal. The current study is aimed at investigating experimentally the effect of various important laser parameters on properties of surface after laser processing. Rusted mild steel samples were irradiated with moving pulsed laser beam. Parameters like scan speed, number of passes, etc. were varied and the change in properties such as surface profile, roughness, hardness, etc. of the processed surface were observed along with depth of removal. The depth of removal was found to increase with an increase in laser power, and number of scans but decreased with an increase in scan speed. The surface got discoloured and deformed at lower speeds and higher powers. The surface roughness after processing hardly showed any variation with the initial roughness values before cleaning but depended on the scanning path of the laser. The microhardness values after laser processing varied with path traced by the laser beam which points to microstructure changes in the samples due to laser processing.