The effect of post-processing operations on mechanical characteristics of 304L stainless steel fabricated using laser additive manufacturing

Abstract

Metal additive manufacturing (AM) is an innovative method for fabricating products used in aerospace, automobile, and medical industries. Research on AM has been extensively conducted because AM can be applied to fabricate features and shapes difficult or impossible to produce using conventional machining (CM) method. However, a problem with this method is the low surface quality of the fabricated product, which necessitates post-processing after the AM process. In this study, CM and induction-assisted machining (IAM) were performed to improve the cutting force, surface roughness, hardness, and microstructure of 304L stainless steel fabricated through AM. First, a 304L stainless steel workpiece was fabricated through AM using metal powder and direct energy deposition. Before the IAM, a thermal analysis was performed to determine the effective depth of cut. After post-processing, the cutting force and surface roughness were measured to investigate the machining characteristics. It was confirmed that the hardness increased because of work hardening, thermal treatment effect and grain growth after CM and IAM. Therefore, CM and IAM can be used for post-processing to improve the machinability, hardness, and microstructure of the fabricated AM product.