A lumped parametric analytical model for predicting molten pool temperature and clad geometry in pre-placed powder laser cladding

Abstract

Pre-placed powder laser cladding is one of the simplest laser-based deposition techniques, having high material usage efficiency and capable to provide sound clad quality. However, the quality along with the geometrical aspects of the deposited layer depends on various energy transfer mechanisms controlled by process parameters. Energy transfer phenomena include the partial absorption of the laser radiation by metal powder layer, melting of the powder layer and transmission of energy to the substrate, along with the losses, like convective heat transfer to the atmosphere and conductive heat transfer to the bulk material. Theses phenomena all together defines the molten pool temperature, which needs to be analyzed to control the geometrical features of the clad and dilution by optimizing the process parameters. Therefore, a lumped parametric analytical model has been formulated and presented in this work for the pre-placed laser cladding process considering energy transfer and loss mechanisms along with the surface tension phenomena of the molten material to predict the molten pool temperature, clad geometry and substrate dilution. The developed model is validated using the experimental results of molten pool temperature of the clad layer, clad width and height as well as the percentage dilution. A continuous mode Yb-Fiber laser system with maximum available laser power of 220 W is used for the deposition of Inconel 625 powder on AISI 304 stainless steel substrate.