Microstructural characteristics and tribological properties of the localized laser surface treatment of AISI 420 stainless steel

In this study, a localized laser surface treatment (LLST) of AISI 420 including transformation hardening and surface melting processes was utilized using a high-power diode laser (HPDL) under different beam travel speeds in order to obtain transformed hardened and surface melted samples. Microstructural characteristics of the laser processing areas were evaluated using field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS). Moreover, the tribological properties of the as-received, transformed hardened and surface melted samples were investigated. Obtained tribological results indicated that the surface melted sample has a higher coefficient of friction (COF) and greater sliding wear rate compared with the transformed hardened sample due to the increment of surface roughness and formation of delta-ferrite precipitates respectively.