Influence of laser processing parameters on the surface characteristics of 316L stainless steel manufactured by selective laser melting

Abstract

Surface quality of metallic components has a huge influence on the wear, fatigue, and eventually service life of the part. Scanning of high-energy laser beams on metal powders during the layer-by-layer melting and solidification process by Selective Laser Melting (SLM) method has been determined to affect the mechanical characteristics and surface integrity of the sintered product. Some of the major processing parameters that have potential influences on material properties, and can affect the quality of the final product have been identified as laser power and scanning speed. These parameters also influence the surface characteristics and quality of the engineered components. This study focuses on the effect of the processing parameters on the surface characteristics SLM parts. Surface morphology, material defects such as pores, voids, cracks, melt pool formation, and chemical elements distribution on 316L stainless steel samples produced with a different combination of power-speed inputs were investigated. Increased laser power resulted in wider melt pools and improved surface texture for all samples, whereas higher scanning speed led to detrimental defects, discontinuity, pores and cracks on the surfaces. Detailed analysis showed that laser power has more effects on the melt pool developments. Chemical element distribution throughout the melt pools revealed carbon and oxygen concentration at melt pool boundaries, which ultimately would induce cracks and balling effects in overlapped regions.