Effect of Shot-Peening Duration on Surface Integrity of Selective Laser Melted Steel Components

Additive manufacturing, particularly Selective Laser Melting (SLM), has emerged as a transformative technology for fabricating complex metallic components; however, surface roughness, porosity, and tensile residual stresses remain major challenges limiting its industrial deployment. Addressing these issues requires efficient post-processing strategies capable of enhancing surface integrity without altering SLM parameters. In this study, Fe–Ni–Cu steel alloy specimens were fabricated using an EOSINT M-۲۵۰ Xtended SLM machine equipped with a ۱۰۰ W fiber laser, and the influence of shot-peening duration on their mechanical and surface properties was investigated. Four samples were prepared—one as a reference and three subjected to peening for ۴, ۶, and ۹ min. Comprehensive analyses were performed, including microhardness testing, surface roughness measurements, SEM observation, Clemex image analysis, and X-ray diffraction residual-stress assessment. Results showed that extending the peening duration from ۴ to ۹ min progressively improved surface quality and stress state: surface roughness decreased by ۶۶.۳%, microhardness increased by ۲۰.۸%, and the initial tensile residual stress of +۱۳۵ MPa was converted into a compressive stress of about –۳۲۲ MPa. Surface porosity also dropped from ≈ ۲۱% to below ۱۰%, confirming effective pore closure and densification of the upper layers. These findings demonstrate that controlled shot-peening, particularly within the ۶–۹ minute range, is a simple yet highly efficient post-processing method for improving the surface integrity and mechanical performance of SLM-fabricated Fe–Ni–Cu steel components

کلیدواژه ها:

Additive Manufacturing ، Selective Laser Melting (SLM) ، Shot-peening ، Surface integrity