Coupled arc and droplet model of GMAW

Abstract

A model of gas metal arc welding was developed that solves the magnetohydrodynamic equations for the flow and temperature fields of the molten electrode and plasma simultaneously, to form a fully coupled model. A commercial finite-element code was extended to include the effects of radiation, Lorentz forces, Joule heating and thermo-electric effects. The model predicts the shape of the free surfaces of the molten metal as the droplets form, detach, and merge with the weld pool. It also predicts the flow, temperature, and electric field. Material properties and the welding parameters are the input variables in the model. The geometry of the numerical model was constructed to fit an experimental apparatus using an aluminium electrode and an argon shielding gas. Droplet frequency measurements were used to verify the model's predictions. For a typical arc, the temperature of the plasma can range up to 20 000 K, where there is more uncertainty in the thermophysical properties of the plasma, and the properties in this range are highly non-linear. For this range, the material properties of the model were adjusted to obtain a better fit between the numerical and the experimental results. The model and experimental results were comparable.

Arc physics based heat source modelling for numerical simulation of weld residual stress and distortion

“…and j r~{ kE r , j z~{ kE z (6) where r is the radial distance, t is the time, H is the enthalpy, p is the pressure, v r and v z are the radial and axial velocities, j r and j z are the radial and axial components of the current density, g is the acceleration due to gravity, c is the specific heat, l is the thermal conductivity, r is the density, t is the viscosity, y is the radiative emission coefficient and k is the electrical conductivity. E r and E z are the radial and axial components of the electric field defined by…”

Analysis and Improvement of Metal Transfer Behaviors in Consumable Double-Electrode GMAW Process

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Analysis of the influence of shielding gas mixtures on the gas metal arc welding metal transfer modes and fume formation rate

“…The physical phenomena involved in this welding process are of complex nature, requiring knowledge of electricity, magnetism, hydrostatics and fluid and gas dynamics [2].…”