PSI - Issue 83

E.N.T. Isidro et al. / Procedia Structural Integrity 83 (2026) 171–178

172

1. Introduction Additive manufacturing (AM) constitutes a fundamental element of Industry 4.0 and serves as a significant catalyst for contemporary industrial advancement. Distinct from conventional subtractive or formative manufacturing techniques, AM constructs objects incrementally, layer by layer. This approach facilitates intricate and optimized geometries and diminished material waste (Naboni and Zomparelli 2023). Within the realm of metals, the technology has experienced swift progress, facilitating the production of functional components for demanding industries including automotive, biomedical, tooling, and aerospace sectors (Sivasubramanian et al. 2025). Selective Laser Melting (SLM) distributes thin layers of metal powder and selectively fuses them using a high-power laser beam (Seydgazov and Mirzade 2021). Typically, fibre lasers with power levels up to 1000 W are employed, with layer thicknesses ranging from 10 to 100 μm and powder particle sizes between 10 and 50 μm. An inert atmosphere, such as nitrogen or argon, is utilized to minimize oxygen exposure and prevent powder ignition; furthermore, support structures are generally necessary to mitigate distortion and facilitate heat dissipation (Silva et al. 2023). The (SLM) process encompasses intricate phenomena such as heat transfer, vaporization, laser absorption, and chemical reactions (Sing et al. 2021). Precise control of process parameters is crucial for attaining the intended geometry, mechanical characteristics, and microstructure (Sefene 2022). Critical parameters encompass laser power, scan spacing, scan speed, deposition strategy, layer thickness, and volumetric energy density (VED) (Silva et al. 2023). Laser power governs the heat input and the energy imparted to the material (Zhu et al. 2022). Scan spacing dictates the separation between successive laser tracks (Wischeropp 2021). Scan speed influences manufacturing duration (Silva et al. 2023), whereas deposition strategy (e.g., single-pass, cross-hatch, chessboard) affects microstructure, mechanical properties, and residual stresses (Sefene 2022). Layer thickness substantially influences productivity, and VED functions as an indicator of thermal intensity; an optimal VED facilitates the production of dense components with superior surface quality, whereas inadequate energy results in lack-of-fusion porosity, and excessive energy induces keyhole porosity and elevated residual stresses (Silva et al. 2023). Extensive research has been conducted on the influence of selective laser melting (SLM) parameters on the density, hardness, and other characteristics of alloys, including Ti-6Al-4V and 316L stainless steel (Ferreira et al. 2021). Maraging steel 1.2709, a precipitation-hardenable alloy characterized by a low-carbon martensitic matrix and intermetallic precipitates, has been a focal point of investigation. This particular alloy is characterized by its considerable strength, hardness, and toughness, making it suitable for a wide range of applications, including tools, injection moulds, and aerospace components (Maodzeka et al. 2023). Conversely, SLM presents certain challenges, including microstructures resulting from rapid solidification, such as retained austenite, as well as porosity, build-orientation anisotropy, and increased surface roughness, all of which can adversely impact fatigue performance (Kučerová et al. 2023) . Therefore, a thorough assessment of density, surface roughness, and hardness is essential for determining the suitability of 1.2709 maraging steel made using SLM for industrial applications. This study examines the relationship between the SLM process settings and the resulting properties of 1.2709 maraging steel in its initial state. 2. Materials and methods 2.1. Printing equipment and material selection The maraging 1.2709 steel powder, was supplied by HASCO. This metal powder was produced through a vacuum gas atomization process, which ensures particles with elevated purity, a sphericity exceeding 92%, and an apparent density below 4.00 g/cm³. The chemical composition is detailed in Table 1.

Table 1. Chemical composition of the maraging steel 1.2709 (%m/m).

Fe

C Cr

Mn Mo Ni

P

S

Si

Co

Ti

Min. Max.

Bal

-

-

-

4.50 17.00

-

-

-

8.50 0.50

- 0.03 0.25 0.15 5.20 19.00 0.01 0.01 0.10 10.00 0.80