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-250 xtended slm machine equipped with a 100 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 4, 6, and 9 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 4 to 9 min progressively improved surface quality and stress state: surface roughness decreased by 66.3%, microhardness increased by 20.8%, and the initial tensile residual stress of +135 mpa was converted into a compressive stress of about –322 mpa. surface porosity also dropped from ≈ 21% to below 10%, confirming effective pore closure and densification of the upper layers. these findings demonstrate that controlled shot-peening, particularly within the 6–9 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 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-250 xtended slm machine equipped with a 100 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 4, 6, and 9 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 4 to 9 min progressively improved surface quality and stress state: surface roughness decreased by 66.3%, microhardness increased by 20.8%, and the initial tensile residual stress of +135 mpa was converted into a compressive stress of about –322 mpa. surface porosity also dropped from ≈ 21% to below 10%, confirming effective pore closure and densification of the upper layers. these findings demonstrate that controlled shot-peening, particularly within the 6–9 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.