Modeling of Metal Transfer in Short Circuiting Arc Welding

2004 ◽  
Author(s):  
Guo Xu ◽  
William W. Schultz ◽  
Elijah Kannatey-Asibu ◽  
S. Jack Hu ◽  
Pei-Chung Wang
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Marangoni Effect ◽  
Welding Current ◽  
Metal Transfer ◽  
Vof Model ◽  
Metal Arc Welding ◽  
Method Effects ◽  
Velocity Pressure ◽  
First Time

The short-circuiting metal transfer during gas metal arc welding (GMAW) is simulated by a numerical model. To the best of our knowledge, for the first time the energy equation and the Marangoni convection are considered in analyzing the short-circuiting time. A front-tracking free surface method is applied to explicitly track the bridge profile. To benchmark this method, effects of the density and viscosity ratios between different phases are investigated by simulating a drop driven by surface tension. The temporal profile of the drop is compared to that computed by a Volume of Fluid (VOF) model, and very good agreement is found. The model is then applied to simulate GMAW short-circuiting transfer. The velocity, pressure, temperature and electromagnetic fields are calculated. Effects of welding current and Marangoni shear stress on short-circuiting time are examined. It is shown that the Marangoni effect plays an important role in GMAW short-circuiting transfer.

Application of a Front Tracking Method in Gas Metal Arc Welding (GMAW) Simulation

2004 ◽  
Vol 127 (3) ◽  
pp. 590-597 ◽  
Author(s):  
Guo Xu ◽  
William W. Schultz ◽  
Elijah Kannatey-Asibu
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Front Tracking ◽  
Front Tracking Method ◽  
Surface Method ◽  
Metal Arc Welding ◽  
Initial Drop ◽  
Velocity Pressure ◽  
First Time

A numerical model is developed to simulate the short-circuiting metal transfer process during gas metal arc welding (GMAW). The energy equation and the Marangoni convection are considered for the first time in analyzing the short-circuiting time. A front-tracking free surface method explicity tracks the profile of the liquid bridge. The electromagnetic field, distribution of velocity, pressure, and temperature are calculated using the developed model. Effects of welding current, surface tension temperature coefficient, and initial drop volume on short-circuiting duration time are examined. The results show that both the electromagnetic force and Marangoni shear stress play significant roles in short-circuiting transfer welding.

Simulation of Gas Metal Arc Welding Short Circuiting Transfer Using a Front Tracking Method

Manufacturing ◽  
2002 ◽  
Author(s):  
Guo Xu ◽  
Elijah Kannatey-Asibu ◽  
William W. Schultz ◽  
P. C. Wang
Keyword(s):  
Shear Stress ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Front Tracking ◽  
Front Tracking Method ◽  
Metal Arc Welding ◽  
Initial Drop ◽  
Velocity Pressure ◽  
First Time

A numerical model is developed to simulate the short-circuiting metal transfer process during gas metal arc welding (GMAW). To our best knowledge, for the first time, the energy equation is considered in analyzing the short-circuiting time, along with the continuity and momentum equations. A front tracking free surface method is implemented to explicitly track the profile of the liquid bridge. The electromagnetic field, distribution of velocity, pressure, and temperature are calculated using the developed model. Effects of welding current, Marangoni shear stress and initial drop volume on short-circuiting duration time are examined. The results show that both the electromagnetic force and Marangoni shear stress play significant roles in the short-circuiting transfer.

scholarly journals Weld Pool Dynamics and the Formation of Ripples in 3D Gas Metal Arc Welding

2007 ◽  
Author(s):  
J. Hu ◽  
H. Guo ◽  
H. L. Tsai
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Present Model ◽  
Gas Metal Arc Welding ◽  
Marangoni Effect ◽  
Surface Tension Force ◽  
Plasma Arc ◽  
Droplet Impingement ◽  
Metal Arc Welding ◽  
First Time

This article studies the transient weld pool dynamics under the periodical impingement of filler droplets that carry mass, momentum, thermal energy, and species in a moving 3D gas metal arc welding. The complicated transport phenomena in the weld pool are caused by the combined effect of droplet impingement, gravity, electromagnetic force, plasma arc force, and surface tension force (Marangoni effect). The weld pool shape and the distributions of temperature, velocity, and species in the weld pool are calculated as a function of time. The phenomena of “open and close-up” for a crater in the weld pool and the corresponding weld pool dynamics are analyzed. The commonly observed ripples at the surface of a solidified weld bead are, for the first time, predicted by the present model. Detailed mechanisms leading to the formation of ripples are discussed.

Modeling Heat and Mass Transfer and Fluid Flow in Three-Dimensional Gas Metal Arc Welding

Manufacturing ◽  
2002 ◽  
Author(s):  
Y. Wang ◽  
H. L. Tsai ◽  
S. P. Marin ◽  
P. C. Wang
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Three Dimensional ◽  
Marangoni Effect ◽  
Surface Tension Force ◽  
Droplet Impingement ◽  
Metal Arc Welding ◽  
Welding Direction ◽  
First Time

This paper extends a mathematical model and numerical techniques previously developed for simulating stationary 2-D gas metal arc welding (GMAW), to moving 3-D GMAW. The filler droplets carrying mass, momentum, thermal energy, and species periodically impinge onto the weld pool, while moving at a certain speed in the welding direction. The complicated transport phenomena in the weld pool are caused by the combined effect of droplet impingement, gravity, electromagnetic force, plasma arc force, and surface tension force (Marangoni effect). The weld pool shape and the distributions of temperature, species, and velocity in the weld pool are calculated as functions of time. For the first time, the phenomena of “open and close-up” for a crater and the formation of ripples at the surface of a solidified weld bead are predicted by mathematical modeling. Under the welding conditions used in the present study, detailed mechanisms leading to the formation of ripples are discussed.

Analytical Modeling of Metal Transfer for GMAW in the Globular Mode

2008 ◽  
Author(s):  
U. Ersoy ◽  
S. J. Hu ◽  
E. Kannatey-Asibu
Keyword(s):  
Gas Metal Arc Welding ◽  
Variable Mass ◽  
Welding Current ◽  
Metal Transfer ◽  
Model Parameters ◽  
Feeding Rates ◽  
Cycle Times ◽  
Metal Arc Welding ◽  
Wire Feeding ◽  
Spring Coefficient

A lumped parameter dynamical model is developed to describe the metal transfer for gas metal arc welding (GMAW) in the globular mode. The oscillations of molten drop are modeled using a mass-spring-damper system with variable mass and spring coefficient. An analytical solution is developed for the variable coefficient system to better understand the effect of various model parameters on the drop oscillations. The effect of welding drop motion on the observed current and voltage signals is investigated and the model agrees well with the experimental results. Furthermore, the effect of wire feeding rate (or welding current) on the metal transfer cycle time is studied and the model successfully estimates the cycle times for different wire feeding rates.

Effect of Current Waveform on Metal Transfer in Controlled Short Circuiting Gas Metal Arc Welding

2013 ◽  
Vol 718-720 ◽  
pp. 202-208 ◽  
Author(s):  
Mao Ai Chen ◽  
Yuan Ning Jiang ◽  
Chuan Song Wu
Keyword(s):  
Transfer Process ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Metal Transfer ◽  
Arc Voltage ◽  
Metal Arc Welding ◽  
Maximum Stability ◽  
The Stability ◽  
Welding Inverter

With high-speed welding inverter and precisely controlling the welding current with arc-bridge state, advanced pulse current waveforms can be produced to optimize the transfer characteristics of short circuiting transfer welding. In this paper, the images of droplet/wire, and the transient data of welding current and arc voltage were simultaneously recorded to study the influence of peak arcing current, background arcing current and tail-out time on the stability of short circuiting transfer process. It was found that maximum short circuiting transfer stability is reached under specific welding conditions. Any deviation from these conditions will cause abnormal rises in arc voltage indicating instantaneous arc extinguishing and greater spatter. Optimal welding conditions were obtained to achieve the maximum stability of short circuiting metal transfer process.

Mechanically assisted droplet transfer process in gas metal arc welding

2002 ◽  
Vol 216 (4) ◽  
pp. 555-564 ◽  
Author(s):  
Y Wu ◽  
R Kovacevic
Keyword(s):  
Transfer Process ◽  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Droplet Transfer ◽  
Macroscopic Appearance ◽  
Transfer Mode ◽  
Metal Arc Welding ◽  
Separate Control

Gas metal arc welding has been generally accepted as the preferred joining technique due to its advantages in high production and automated welding applications. Separate control of arc energy and arc force is an essential way to improve the welding quality and to obtain the projected metal transfer mode. One of the most effective methods for obtaining separate control is to exert an additional force on the metal transfer process. In this paper, the droplet transfer process with additional mechanical force is studied. The welding system is composed of an oscillating wire feeder. The images of molten metal droplets are captured by a high-speed digital camera, and both the macroscopic appearance and the cross-sectional profiles of the weld beads are analysed. It is shown that the droplet transfer process can be significantly improved by wire electrode oscillation, and a projected spray transfer mode can be established at much lower currents. By increasing the oscillation frequency, the droplet transfer rate increases while the droplet size decreases. In addition, the improvement in the droplet transfer process with wire oscillation leads to an enhancement of the surface quality and a modification of the geometry of the weld beads that could be of importance for overlay cladding and rapid prototyping based on deposition by welding.

Sign in / Sign up

Export Citation Format

Share Document