Investigating the effect of the high power and high speed CO₂ laser surface melting on the residual stresses and corrosion resistance of 316L stainless steel

This study is investigating the effect of the laser surface melting of 316L stainless steel cylindrical samples on the surface residual stresses and the corrosion resistance. A high speed CO₂ laser beam with power range of 300-500 W was used in pulse mode to initiate the surface melting in an argon and argon-nitrogen atmosphere. The produced samples were cross sectioned and the elastic modulus and nano-hardness test were carried out showing no alteration between the modified and the bulk material. A noticeable degradation in the corrosion resistance was found due to the formation of the chromium carbide and chromium nitride which act as electrolytic cells in addition to the disruption of the free chromium content at the melted zone.