Thermal Calibration of Finite Element Models in Wire Arc Directed Energy Deposition of ER-120S-G Using Thermocouples and Infrared Cameras

Abstract As wire arc-directed energy deposition (WA-DED) gains traction in the manufacturing industry, optimizing process efficiency for metallic alloys such as ER120S-G remains challenging due to the high costs and time demands of physical trials. This study addresses these challenges by thermally calibrating a finite element model (FEM) for ER120S-G, a high-strength steel alloy used in heavy construction and large vehicles. Calibration was achieved using thermocouples and infrared (IR) imaging to record thermal history during the WA-DED process. Thermal data were collected using six thermocouples placed on the substrate and an IR camera capturing surface temperatures. To ensure accurate IR readings, the camera’s emissivity was calibrated by comparing its data with thermocouple readings for both machined and non-machined ER120S-G surfaces. FEM simulations were performed in Abaqus, utilizing the Goldak double-ellipsoid heat source model to simulate the WA-DED thermal process. Key parameters, including power efficiency, emissivity, and heat transfer coefficients, were systematically varied to assess their impact. The parametric study revealed that power efficiency and heat transfer coefficients significantly influence the overall thermal history, while the Goldak parameters primarily affect the melt pool. Calibration involved adjusting these variables until the FEM output closely matched experimental data. Optimal power efficiency and heat transfer coefficients were identified for the two experimental setups, highlighting the heatsinks critical role in substrate cooling. The calibrated FEM was validated by comparing its predictions with experimental results, demonstrating its reliability in simulating thermal histories under varying conditions. This model provides a cost-effective tool for optimizing WA-DED processes, reducing dependence on physical trials while improving predictive accuracy for mechanical performance.