A Study on the Enhancement of Chemical and Mechanical Properties of Low Carbon Steel Surface Cleaned with a Nanosecond Pulsed Laser

Laser cleaning has been observed to alter the surface properties of steel surfaces.The change in surface properties is greatly affected by the laser parameters and therefore, the selection of appropriate laser parameters is paramount.In this work, a study on the treatment combination of laser power, scan speed, pulse repetition rate, and hatch distance on the surface hardness and the mass percentage of iron is conducted via response surface methodology using a central composite design.The factors and interactions that significantly affect the response were identified by analysis of variance (ANOVA).The microhardness was measured using a Vickers hardness testing machine and the mass percentage of iron was obtained by energy dispersive x-ray spectroscopy (EDS) analysis.The hardness value was observed to remain almost unchanged or increase by more than 200 % and steel was completely reduced to even 100 % pure iron at different laser parameters.The responses were approximated by a second-order regression model and the R-squared values for the models of hardness and mass percentage of iron are 84 % and 80 % respectively.The model can be used to predict the parameters that result in the desired surface hardness and iron content during cleaning.