PSI - Issue 77

Jakob Blankenhagen et al. / Procedia Structural Integrity 77 (2026) 198–206 Author name / Structural Integrity Procedia 00 (2026) 000–000

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1. Introduction

Additive Manufacturing (AM) has emerged as one of the fastest-growing production technologies across diverse industries. Among the various AM processes, Powder Bed Fusion with a Laser Beam for metals (PBF-LB / M) is par ticularly prominent due to its ability to manufacture near-net-shape components with minimal geometric restrictions. This enables the fabrication of highly complex geometries, shape-optimized parts, and architected materials such as lattice structures. Lattice designs, including auxetic topologies with negative Poisson’s ratios, illustrate the capability of AM to embed functionality directly into material architecture (Vitalis et al. (2024); Frasch et al. (2024)). Such features are typically exploited to reduce weight, improve sti ff ness, or tailor structural response. Beyond lightweight applications, the integration of AM into structural engineering o ff ers significant potential. Op timized nodes and joints can enhance global load paths, improve structural e ffi ciency, and expand architectural design freedom. Free-formed steel–glass ceilings and fac¸ades highlight the importance of design flexibility in large-scale steel construction, a domain where AM could provide further advancements. A prominent example is the Fiera Milano ex hibition hall, which contains more than 16,000 nodes, most of which are geometrically unique. For AM processes such as PBF-LB / M, the number of di ff erent node geometries—whether ten or several thousand—has only a marginal impact on the manufacturing e ff ort. (Diller et al. (2023)) However, despite these opportunities, the implementation of AM in construction remains limited, primarily due to the size constraints of current processes. A viable pathway is therefore the hybridization of AM components with conventionally manufactured semifinished elements, like tubes andbeams. The joining of such hybrid systems presents a critical challenge. While mechanical fastening methods such as bolt ing and riveting are possible, welding o ff ers superior potential for e ffi cient force transmission and material utilization. Welding of PBF-LB / M manufactured austenitic steels is studied quite commonly, as shown by (Faes et al. (2024)). Yet, dissimilar welds between AM and conventional steels remain infrequently studied. The challenge arises from the di ff erence in phase composition: in AM austenitic stainless steels, aluminum, titanium, or nickel-based alloys are commonly used, whereas construction predominantly relies on structural steels such as S460NL. Which has a ferritic pearlitic grain structure (Markowski et al. (2007)). Consequently, ”black-and-white” welded joints between dissimilar microstructural steels-must be carefully characterized to ensure mechanical integrity. To address this gap, the present study investigates dissimilar welded joints between additively manufactured high manganese, fully austenitic C + N steel Printdur ® HSA and structural steel S460NL. The AM plates were produced by PBF-LB / M and subsequently joined to S460NL plates using two approaches: laser welding without filler and Metal Inert Gas (MIG) welding with G 18 8 Mn filler. The mechanical performance of the joints was evaluated by tensile testing with Digital Image Correlation (DIC) to capture strain localization and failure mechanisms. In addition, the mechanical behavior of the heat-a ff ected zone (HAZ) of the AM steel was studied through controlled heat treatments at di ff erent peak temperatures and cooling rates, thereby enabling a deeper understanding of the mechanical response relevant for the structural integrity of the dissimilar weld joint. The investigated materials were Printdur ® HSA as the additively manufactured alloy, S460NL as the structural steel, and G 18 8 Mn as the filler material for MIG welding. Their material properties are summarized in Table 1. The data for Printdur ® HSA were taken from (Blankenhagen et al. (2025)), the properties of S460NL from the man ufacturer’s inspection certificate, and the filler data from the supplier’s datasheet (ESAB (2025)). The mechanical performance of the S460NL steel is lower than that of the other materials in the joint. Therefore, the objective is to reach the S460NL level with the welded joint. Test plates with dimensions of 200 × 100 × 6 mm were produced. The S460NL plates were die-stamped from hot-rolled, normalized sheets, whereas the Printdur ® HSA plates were manu factured by PBF-LB / Musing an EOSM280 machine. The applied process parameters are listed in Table 2. Nitrogen shielding gas was used to ensure stable processing. No post-processing such as heat treatment or surface finishing was applied to the AM plates. Prior to welding, the plates were machined according to the requirements of the welding process. For the laser welding, the plates were prepared with a 90° edge and a gap of less than 0.1 mm. For the MIG welding, a 30° bevel was machined in the plates. This was done in order to create a 60° V-groove weld preparation, as illustrated in Fig. 1. 2. Experimental Setup