Modeling of Heat Transfer and Fluid Flow in the Laser Multilayered Cladding Process

Abstract

The current work examines the heat-and-mass transfer process in the laser multilayered cladding of H13 tool steel powder by numerical modeling and experimental validation. A multiphase transient model is developed to investigate the evolution of the temperature field and flow velocity of the liquid phase in the molten pool. The solid region of the substrate and solidified clad, the liquid region of the melted clad material, and the gas region of the surrounding air are included. In this model, a level-set method is used to track the free surface motion of the molten pool with the powder material feeding and scanning of the laser beam. An enthalpy-porosity approach is applied to deal with the solidification and melting that occurs in the cladding process. Moreover, the laser heat input and heat losses from the forced convection and heat radiation that occurs on the top surface of the deposited layer are incorporated into the source term of the governing equations. The effects of the laser power, scanning speed, and powderfeed rate on the dilution and height of the multilayered clad are investigated based on the numerical model and experimental measurements. The results show that an increase of the laser power and powder feed rate, or a reduction of 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.

Heat transfer and material flow during laser assisted multi-layer additive manufacturing

“…The initial two-dimensional calculations 21,22 of heat transfer and fluid flow were followed by adaptation of transient, three-dimensional models of laser cladding, 6,7,19,20 and welding 23 to additive manufacturing. Tracking of the free surface was also simulated by the level set method 6,7,19,20,22 which is computationally highly intensive. Furthermore, the quality of the calculations remains to be tested by comparison with any transient experimental tracking of the topology of the free surface.…”

Spatial variation of melt pool geometry, peak temperature and solidification parameters during laser assisted additive manufacturing process

“…In the recent past, three-dimensional heat transfer and fluid flow models have been used to analyse a single layer laser cladding process. [16][17][18] Kong and Kovacevic 19 and Morville et al 20 reported two-dimensional heat transfer and fluid flow models for laser assisted multilayered deposition of H13 tool steel and Ti6Al4V alloy structures respectively. These models used computationally intensive level set method [16][17][18][19] and arbitrary Langrangian-Eulerian 20 moving mesh for the calculations.…”

“…[16][17][18] Kong and Kovacevic 19 and Morville et al 20 reported two-dimensional heat transfer and fluid flow models for laser assisted multilayered deposition of H13 tool steel and Ti6Al4V alloy structures respectively. These models used computationally intensive level set method [16][17][18][19] and arbitrary Langrangian-Eulerian 20 moving mesh for the calculations. Raghavan et al 21 adapted a computationally efficient three-dimensional heat transfer and fluid flow model for welding to examine the effect of process parameters on the melt pool geometry and solidification parameters in additive manufacturing.…”

Multiphysics simulation of laser–material interaction during laser powder depositon

“…The first models incorporating the effect considered a modified thermal conductivity to account for thermo-capillary phenomena of the liquid metal without calculating the fluid flow [20][21][22]. Later, transient models including the entire thermo-capillary problem were developed as shown for single- [23], double-track coaxial [24], and multilayered offaxial cladding [25]. However, an accurate model accounting for all the important phenomena cannot be solved analytically and numerical approaches are still computationally intensive.…”