Modares Mechanical Engineering

Modares Mechanical Engineering

Effect of shot-peening duration on surface integrity of selective laser melted steel components

Document Type : Original Research

Authors
Mohammad Amin Rahimi Jafari 1
Ramin Hashemi 1
Amir Rasti 2
Ali Zeinolabedin-Beygi 2
1 School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
2 Faculty of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran
10.48311/mme.2025.96904.0
Abstract
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.
Keywords
Additive Manufacturing
Selective Laser Melting (SLM)
Shot-peening
Surface Integrity

Subjects

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Modares Mechanical Engineering
Volume 25, Issue 9
September 2025
Pages 581-586