Development and validation of a thermal analysis model for wire arc directed energy deposition applicable to multiple deposition conditions

Abstract In metal additive manufacturing, accurate prediction of the temperature field is important because the thermal history during deposition strongly affects microstructural evolution and mechanical properties. However, thermal analysis of wire arc directed energy deposition often requires identification of parameters such as heat source geometry and thermal efficiency for specific deposition conditions, and recalibration after condition changes can limit model applicability. This study focused on heat transfer from the substrate to the supporting system and aimed to develop a model whose parameters, identified under one condition, could be transferred to different conditions without re-identification. Three models with different representations of heat transfer beneath the substrate were constructed. Parameters were identified using measured thermal histories under one condition and applied unchanged to four additional conditions with different wire feed speeds, torch travel speeds, and interlayer cooling times. A model incorporating a virtual thin plate beneath the substrate, which equivalently represented heat capacity and horizontal heat conduction in the supporting system, maintained good prediction accuracy across five conditions without recalibration, with overall root mean squared error values of 4.81–6.73 K. It also achieved accuracy comparable to that of a detailed supporting-system model with a simpler configuration and shorter computation time. Comparison with measured thermal histories at different heights on the deposited wall showed that the model reproduced the overall trend and post-deposition cooling behavior. These results demonstrate that appropriate representation of heat transfer to the supporting system can reduce condition-specific recalibration and enable transfer of model parameters across multiple deposition conditions.