Modeling of Transport Phenomena in the Laser Multilayered Cladding

The present work studies the heat and mass transfer process in the laser multilayered cladding of H13 tool steel powder by numerical modeling and experimental validation. A solid-liquid-gas unified transient model was developed to investigate the evolution of temperature distribution and flow velocity of the liquid phase in the molten pool. In this model, an enthalpy-porosity approach was applied to deal with the solidification and melting occurring in the clad, and a level-set method was used to track the evolution of the molten pool free surface. Moreover, heat loss due to forced convection and heat radiation and laser heat input occurring on the top surface of deposited layer and substrate have been incorporated into the source term of governing equations. The effects of laser power, scanning speed, and powder feed rate on the dilution and height of the multilayered clad are investigated based on the numerical model and experimental measurement. The results show that increasing the laser power and powder feed rate, or reducing the scanning speed, can increase the clad height and directly influence the remelted depth of each layer of deposition. The numerical results have a qualitative agreement with the experimental measurements.