Numerical simulation of effects of activating flux on flow patterns and weld penetration in ATIG welding

Abstract A mathematical model to describe molten pool of three-dimensional gas tungsten arc welding due to a moving arc has been developed considering the surface tension temperature gradient as a function of temperature and oxygen concentration to simulate the effect of activating flux on flow patterns and weld penetration. The effect of oxygen content and arc constriction on the fluid flows and temperature fields of weld pool has been simulated by the Phoenics software. The effect of activating flux on the penetration has been considered in the model by changing the oxygen content in the surface tension equation and the arc heat flux distribution parameter in Gauss source and magnetic force equations. It is shown that oxygen, which changes the temperature dependence of surface tension gradient ∂γ/∂T from a negative value to a positive value, can cause a significant change in weld penetration. The change in the surface tension gradient in the molten pool is considered to be the principal mechanism for in...

[1]  J. Szekely,et al.  On the calculation of the free surface temperature of gas-tungsten-arc weld pools from first principles: Part II. modeling the weld pool and comparison with experiments , 1992 .

[2]  Thomas Zacharia,et al.  Effect of evaporation and temperature-dependent material properties on weld pool development , 1991 .

[3]  U. Mitra,et al.  Slag-metal reactions during welding: Part II. Theory , 1991 .

[4]  V. Voller,et al.  A fixed grid numerical modelling methodology for convection-diffusion mushy region phase-change problems , 1987 .

[5]  W. Lucas,et al.  Investigation into arc constriction by active fluxes for tungsten inert gas welding , 2000 .

[6]  M. Cross,et al.  An enthalpy method for convection/diffusion phase change , 1987 .

[7]  J. M. Vitek,et al.  Phenomenological Modeling of Fusion Welding Processes , 1994 .

[8]  Manabu Tanaka,et al.  Weld Penetration and Marangoni Convection with Oxide Fluxes in GTA Welding. , 2002 .

[9]  Y M Zhang,et al.  Numerical Analysis of Fully Penetrated Weld Pools in Gas Tungsten Arc Welding , 1996 .

[10]  T. DebRoy,et al.  Development of macro- and microstructures of carbon–manganese low alloy steel welds: inclusion formation , 1995 .

[11]  Manabu Tanaka,et al.  Effects of oxygen additions to argon shielding gas on GTA weld shape , 2003 .

[12]  J. Lowke,et al.  Numerical Analysis for Weld Formation Using a Free-Burning Helium Arc at Atmospheric Pressure , 2005 .

[13]  M. Ushio,et al.  Effects of activating flux on arc phenomena in gas tungsten arc welding , 2000 .

[14]  F. Fiévet,et al.  Preparing Monodisperse Metal Powders in Micrometer and Submicrometer Sizes by the Polyol Process , 1989 .

[15]  K. Nogi,et al.  Weld shape comparison with iron oxide flux and Ar–O2 shielding gas in gas tungsten arc welding , 2004 .

[16]  H. Tsai,et al.  Modeling of the effects of surface-active elements on flow patterns and weld penetration , 2001 .

[17]  T. DebRoy,et al.  Surface tension of binary metal—surface active solute systems under conditions relevant to welding metallurgy , 1988 .

[18]  J. Lowke,et al.  Mechanisms giving increased weld depth due to a flux , 2005 .

[19]  YuMing Zhang,et al.  Numerical dynamic analysis of moving GTA weld pool , 1998 .

[20]  Manabu Tanaka,et al.  Numerical Study of a Free-Burning Argon Arc with Anode Melting , 2003 .