NUMERICAL STUDY OF STEADY-STATE AND TRANSIENT LASER MELTING PROBLEMS .2. EFFECT OF THE PROCESS PARAMETERS

A parametric study of laser melting problems is presented. Using steel (Pr = 0.078) and aluminium (Pr = 0.01), studies are made by varying beam radius (0.5, 1.0 and 2.0 mm) and bean power density (108-109 W m-2). The effects of these parameters are studied on the bulk mean temperature of the liquid, the maximum width and depth of the pool, the area of the solid/liquid interface, the area of the liquid phase and the interface Nusselt number. Comparative studies are performed between pure conduction and convection cases to analyse the effect of convection on the overall heat transfer, and thus the critical values of process parameters are identified below which convection is negligible. The maximum pool width is found to be invariant for beams of varying radii when the product of beam power and radius is constant. Finally, correlations are derived to determine the bulk mean temperature of the liquid, the maximum width and depth of the pool and the interface Nusselt number from the process parameters. © 1990.