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Engineering Science in
Additive Manufacturing Additive manufacturing of EH36 steels

A

B C

Figure 1. Schematic diagram of AM techniques for fabrication of EH36 steels: (A) PBF-LB, (B) DED-LB, and (C) DED-Arc
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Abbreviations: AM: Additive manufacturing; DED-Arc: Direct energy deposition using electric arc; DED-LB: Direct energy deposition using laser beam;
PBF-LB: Powder bed fusion using a laser beam.
their high beam quality, controlled energy input, and using Wire Arc AM, classified as DED-Arc in ASTM
capability to precisely manage melt pool dynamics while terminology, adopts an electric arc to generate a molten
maintaining a higher energy input required for DED-LB. pool into which a consumable metal wire is continuously
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Figure 1B reveals that DED-LB uses a high-energy fed, as shown in Figure 1C. This method enables the layer-
laser beam to create a melt pool for continuous metal by-layer fabrication of metallic components without the
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feedstock deposition. The laser melts the feedstock upon need for a powder bed or build chamber, it is known
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interaction, and rapid solidification enables the layer-by- for its high deposition rates, typically ranging from 3 to
layer construction of near-net-shape components directly 8 kg/h, which are significantly higher than those achievable
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from computer-aided design models. A coaxial nozzle with powder-based AM techniques such as PBF-LB and
setup is often utilized in DED-LB to deliver the powder DED-LB. 51,52 The process is also widely recognized for
and/or wire feedstocks with high precision, minimize its ability to produce large-scale components efficiently,
material wastage, and enhance deposition efficiency. The making it highly suitable for industries such as shipbuilding
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process is typically carried out in an inert atmosphere, such and offshore structures. 53,54
as argon or nitrogen, to minimize oxidation and maintain The EH36 powder used for PBF-LB and DED-LB is
consistent material properties throughout the as-print typically produced through gas atomization, a process
part. This feature, combined with its ability to produce that generates spherical particles with smooth surfaces. 30,33
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large-scale parts and repair or modify existing structures, Spherical morphology is essential for achieving high
makes DED-LB suitable for the production of EH36 steel flowability and uniform layer deposition, both of which
components used in marine and offshore applications. are critical for forming a dense, homogeneous powder
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On the other hand, the fabrication of AMed EH36 steel bed. Furthermore, powders with a narrow particle size

Volume 1 Issue 1 (2025) 3 doi: 10.36922/ESAM025060005