Investigation of the laser effect of micromechanical properties of stainless steel AISI 304 during the marking process

The aim of this study was to investigate the microstructure and micromechanical properties of pulsed laser irradiated stainless steel. Laser marking was performed for AISI 304 stainless steel samples using a Nd:YAG fiber laser (1064 nm). AISI 304 steel finds applications in a variety of industries due to its excellent properties: Automotive and aerospace components; Heat exchangers; Kitchen sinks, consumer durables; Chemical containers, including for transport; Food processing equipment, particularly in beer brewing, milk processing, and wine making; Fasteners and flanges manufacturing; Architectural applications such as roofing and cladding, doors and windows. The influence of the process parameters such as pulse repetition frequency and scanning speed at different topology of the surface treatment is considered. The microstructures of the obtained samples were analyzed using confocal optical microscopy (COM). For each square, the roughness of the marking was determined using specialized software and an established methodology. The roughness was measured repeatedly and the mean value for each square was determined together with the root mean square error. Graphs of the dependence of the roughness on the speed and the raster step were obtained. From them, the rate of change of roughness for different intervals of speed and raster step was calculated. Optimal operating intervals of speed and raster beam were determined for the studied steel and this type of laser.