Microstructural, hardening, and wear characteristics of surface re-melted AISI 410S stainless steel via fiber laser process

AISI 410S ferritic stainless steel was surface melted via a continuous fiber laser at different scan rates. The microstructural characteristics, thickness, hardness, and tribological behavior of the laser melted (LSMed) surface were studied after different scan rates. The hardened layer thickness was inversely related to the scan rate. The thickness reduced from 146 mu m at the scan rate of 15 mm.s(-1) to 110 mu m at the scan rate of 24 mm.s(-1). The microstructural studies revealed that the microstructure of the hardened layers mostly consisted of martensite. At the lowest scan rate, the martensite was in two forms of fine and coarse packets. The surface hardness enhanced with decreasing the scan rate. The maximum average hardness (330 HV) was obtained from the scan speed of 15 mm.s(-1). However, the most surface hardness scattering was observed in the sample treated by the lowest scan speed. The sample treated using the moderate scan rate (20 mm.s(-1)) demonstrated superior wear resistance due to its lowest coefficient of friction (COF) and weight loss. The reason for this behavior could be related to the appropriate melted thickness. Microstructural studies revealed that abrasive wear and adhesive wear were the dominant mechanisms in the worn surfaces.