Researchers from Oak Ridge National Laboratory, working with industry partner ARC Specialties, have developed and demonstrated a new high-throughput metal additive manufacturing process designed for producing large, near-net-shape components. The technique, termed Electroslag Additive Manufacturing (ESAM), combines electroslag strip cladding (ESC) with wire arc additive manufacturing (WAAM) to achieve deposition rates several times higher than conventional wire-based AM processes.
Published in Additive Manufacturing Letters, the study evaluates ESAM using Alloy 625 and demonstrates that the process can deliver mechanical properties comparable to cast material while significantly increasing build rate. According to the authors, the approach could support the production of multi-ton components currently manufactured using casting and forging, particularly in energy-sector applications.
Combining electroslag productivity with wire-arc precision
ESC is a welding-based process known for its high deposition rates but has historically been difficult to apply in additive manufacturing due to challenges in containing molten slag and weld pools. To address this, the researchers combined ESC with WAAM, using gas tungsten arc welding (GTAW) to build retaining walls that confine the ESC deposition region.
This convergent, multi-process approach allows ESAM to pair the high productivity of ESC with the geometric control of WAAM. In the study, the team demonstrated the method by producing an annular geometry in which GTAW-built walls were subsequently infilled using ESC.
Evaluating stacking strategies and material behavior
As a precursor to the convergent process, the researchers first investigated ESC used independently in an additive context. Two bead-stacking strategies were evaluated: Direct stacking (ESAM-D) and Staggered stacking (ESAM-S).
Microstructural analysis showed strong ⟨001⟩ build-direction texture in both strategies, with iron dilution from the steel substrate largely confined to the first deposited layer. Mechanical testing revealed that direct stacking produced slightly higher yield and ultimate tensile strength, while staggered stacking resulted in significantly higher ductility. The authors attribute these differences primarily to variations in iron dilution and resulting deformation mechanisms.
Convergent ESAM shows consistent properties across interfaces
When ESC infill was combined with GTAW retaining walls in the full ESAM configuration, microstructural and nanoindentation analysis indicated that the presence of GTAW walls did not adversely affect material properties. Hardness and elastic modulus remained consistent across the GTAW, ESC, and interface regions, and grain misorientation measurements suggested minimal plastic strain accumulation.
The authors report that ESAM-produced Alloy 625 exhibited tensile properties comparable to cast material, supporting the feasibility of scaling the process to components exceeding one metric ton.
Higher build rates than wire-fed WAAM
Deposition rate measurements showed that ESC-based ESAM achieved build rates of approximately 22.7 kg/h in ESC-only configurations and 11.3 kg/h for ESC infill in the convergent setup. These rates are reported to be three to six times higher than wire-fed WAAM, while maintaining comparable mechanical performance.
Outlook for large-scale industrial adoption
The research team is now developing a fully robotic ESAM workcell integrating coordinated ESC and GMAW systems, with the aim of advancing the process from laboratory-scale demonstrations to an automated manufacturing platform. Future work will focus on larger test articles, full-size mechanical testing, and advanced capabilities such as in-situ alloying and functional material grading.
According to the authors, ESAM provides a potential pathway for accelerating additive manufacturing adoption in applications requiring large, near-net-shape metal components, particularly where build rate and supply-chain resilience are critical considerations.
Researchers explore alternative approaches to scaling metal additive manufacturing
Related research highlights parallel efforts to improve throughput and process control in metal additive manufacturing. Recent studies have demonstrated how machine learning techniques can be applied to direct energy deposition (DED) processes to improve monitoring, stability, and predictive control, addressing challenges associated with scaling metal AM for industrial use.
In a separate development, Belgian startup ValCUN has introduced a molten metal deposition approach for aluminium, positioning the technology as a wire-based alternative to powder-based metal AM systems. Together, these efforts reflect a broader trend toward higher deposition rates, alternative energy and feedstock strategies, and improved process robustness aimed at supporting large-scale and cost-sensitive production applications.
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Featured image shows an Alloy 625 annular geometry produced using Electroslag Additive Manufacturing (ESAM), combining GTAW-printed retaining walls with ESC infill. Image via Stevens et al.
