In this study the heat transfer, fluid flow and phase change of the we
ld pool in pulsed current gas tungsten are (GTA) welding were investig
ated. Transporting phenomena from the welding are to the base material
surface, such as current density, heat flux, are pressure and shear s
tress acting on the weld pool surface, were taken from the simulation
results of the corresponding welding are. Various driving forces for t
he weld pool convection were considered, namely self-induced electroma
gnetic, surface tension, buoyancy, and impinging plasma are force. Fur
thermore, the effect of deformed free surface due to the are pressure
acting on the weld pool surface was considered. Heat and mass transfer
equations, including the generalized Navier-Stokes equation and elect
ric transport equation, were solved by a finite difference method. Bec
ause the fusion boundary has a curved and unknown shape during welding
, a boundary-fitted coordinate system was adopted to precisely describ
e the boundary for the momentum equation. The numerical model for puls
ed: current welding was applied to AISI 304 stainless steel and compar
ed with the results of the constant current. (C) 1998 Elsevier Science
Ltd. All rights reserved.