Impact of dual beams on flow characteristics in weld pool

Abstract

Fluid flow and heat transfer during dual-beam laser welding is analyzed. The objective of this investigation is control of flow in the weld pool and its impact on the resultant weld pool geometry and solidification. It is based on a transient two-dimensional finite volume numerical simulation of flow in a moving plate for a dual heat source. Each of the two laser beams at the top surface of the weld pool is modeled as a Gaussian source. The heat transfer mechanisms considered include conduction in the solid region, natural and Marangoni convection in the liquid region. The change in the fluid flow structure induced by imposing a second laser beam affects the weld pool shape. The pool geometry, temperature, and velocity fields that result during dual-beam laser welding are compared with those of a single beam laser welding process for different inter-beam spacings and surface tension temperature coefficients for stainless steel 304. Representative results of the flow and temperature distribution in the weld pool for the single and dual-beam laser welding processes are reported graphically in the form of liquid phase isotherm, stream functions and velocity vectors at specified times.Fluid flow and heat transfer during dual-beam laser welding is analyzed. The objective of this investigation is control of flow in the weld pool and its impact on the resultant weld pool geometry and solidification. It is based on a transient two-dimensional finite volume numerical simulation of flow in a moving plate for a dual heat source. Each of the two laser beams at the top surface of the weld pool is modeled as a Gaussian source. The heat transfer mechanisms considered include conduction in the solid region, natural and Marangoni convection in the liquid region. The change in the fluid flow structure induced by imposing a second laser beam affects the weld pool shape. The pool geometry, temperature, and velocity fields that result during dual-beam laser welding are compared with those of a single beam laser welding process for different inter-beam spacings and surface tension temperature coefficients for stainless steel 304. Representative results of the flow and temperature distribution in the wel...