Development of a Numerical Model for Coaxial Wire Laser Cladding Using 316L Stainless Steel

Wire laser cladding (WLC) provides high material utilization, controllable material feeding, and reduced feedstock loss compared with powder-based laser cladding. In this study, a three-dimensional transient computational fluid dynamics model was developed for coaxial WLC using 316L stainless steel as both the wire and substrate material. The wire was explicitly included in the computational domain, while the six individual laser beams were represented as three-dimensional flat-top heat sources acting on the evolving metal–gas interface. The model incorporated heat transfer, melting and solidification, free-surface deformation, and Marangoni convection using the volume-of-fluid (VOF) and enthalpy-porosity methods. Three linear energy density conditions were investigated while maintaining a constant ratio between wire feeding speed and deposition speed. The predicted clad height, width, side angle, and geometrical dilution rate were compared with experimental cross-sectional measurements. The mean absolute percentage errors were approximately 13.0%, 7.7%, 9.1%, and 6.0%, respectively. Good agreement was obtained under the intermediate and reference conditions, while the largest deviation occurred at the highest linear energy density. Across the investigated conditions, lower linear energy density was associated with a lower maximum temperature, a wire melting front closer to the substrate, a smaller molten region, and a lower deposited-track height. The developed model provides a physics-based tool for predicting track formation and supporting process-design evaluation in coaxial 316L stainless steel WLC.