A Study on the Three-Dimensional Analysis of Heat and Fluid Flow in Gas Metal Arc Welding Using Boundary-Fitted Coordinates

Abstract

Computer simulation of three-dimensional heat transfer and fluid flow in gas metal arc (GMA) welding has been studied by considering the three driving forces for weld pool convection, that is the electromagnetic force, the buoyancy force, and the surface tension force at the weld pool surface. Molten surface deformation, particularly in the case of GMA welding, plays a significant part in the actual weld size and should be considered in order to accurately evaluate the weld pool convection. The size and profile of the weld pool are strongly influenced by the volume of molten electrode wire, impinging force of the arc plasma, and surface tension of molten metal. In the numerical simulation, difficulties associated with the irregular shape of the weld bead have been successfully overcome by adopting a boundary-filled coordinate system that eliminates the analytical complexity at the weld pool and bead surface boundary. The method used in this paper has the capacity to determine the weld bead and penetration profile by solving the surface equation and convection equations simultaneously.

2-D Finite Element Modeling of Gma Welding Process.

“…Generally, mathematical modeling approaches for describing the phenomena happened during the arc welding and investigating how the process parameters affect the weld quality, have become an essential and systematic technique. A number of researchers [1][2][3][4][5][6][7][8][9][10][11][12] have reported that convection in weld pools can strongly affect the weld bead dimension and the structure of the resultant welds. The early studies regarding weld pool convection have mainly been done through experiments [1][2].…”

“…However, a number of previous researchers considered only the first three forces, but the drag force was not included as the driving force for mathematical model [6,8]. Even the situation has altered greatly with the advent of increasing computer efficiency and better understanding of the physics of welding, only two papers were found as showed by a few people [9][10]. Tsao and Wu [9] first presented a mathematical model employing the vorticity stream function and implicit finite difference method, but ignored the flow induced by the droplet surface interactions and arbitrarily fixed the parameters of volumetric heat source.…”

Weld pool dynamics and the formation of ripples in 3D gas metal arc welding

“…The plasma arc pressure is assumed to have a radial distribution in the moving rz cylindrical coordinate system for the following form [25]:…”

“…Ushio and Wu [25] used a boundary-fitted non-orthogonal coordinate system to handle the largely deformed GMA weld pool surface and predicted the area and configuration of weld reinforcement. In their study, the heat delivered by metal transfer was approximated by an internal heat-generation term and the impact of droplets on the weld pool was considered to be a constant force acting on the surface.…”

A Study of Heat Input Distribution on the Surface during Torch Weaving in Gas Metal Arc Welding

“…Tsao and Wu (1988) (3) presented a 2-dimensional heat transfer model in GMAW, while Tekriwal and Mazumder (1988) (4) suggested a 3-dimensional model. Later, Kim and Na (1994) (5) were able to make more accurate temperature distribution estimations through 3-dimensional temperature distribution explanations using boundary-fitted coordinates. The above studies are all explanations of bead on plate welding.…”