Effect of welding current on arc behavior in tandem GMAW

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940036
Author(s):  
Juan Pu ◽  
Shan Wu ◽  
Qingxian Hu ◽  
Yuxin Wang

A three-dimensional numerical model of double-arc in tandem gas metal arc welding (GMAW) was established based on the theory of arc physics, momentum equation, energy equation, continuous equation and Maxwell equations. The effects of different welding current on temperature field, velocity field and pressure field on the surface of workpieces were investigated. The results showed that the maximum values of arc temperature, arc plasma velocity and arc pressure on workpieces surface were increased with the increasing welding current. These maximum values occurred at the tip of double-wire. The current density and axial deflection angle of coupling arc were increased following the increasing welding current.

Author(s):  
J. Hu ◽  
H. L. Tsai

This article analyzes the dynamic process of groove filling and the resulting weld pool fluid flow in gas metal arc welding of thick metals with V-groove. Filler droplets carrying mass, momentum, thermal energy, and sulfur species are periodically impinged onto the workpiece. The complex transport phenomena in the weld pool, caused by the combined effect of droplet impingement, gravity, electromagnetic force, surface tension, and plasma arc pressure, were investigated to determine the transient weld pool shape and distributions of velocity, temperature, and sulfur species in the weld pool. It was found that the groove provides a channel which can smooth the flow in the weld pool, leading to poor mixing between the filler metal and the base metal, as compared to the case without a groove.


Author(s):  
U. Ersoy ◽  
S. J. Hu ◽  
E. Kannatey-Asibu

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.


2013 ◽  
Vol 718-720 ◽  
pp. 202-208 ◽  
Author(s):  
Mao Ai Chen ◽  
Yuan Ning Jiang ◽  
Chuan Song Wu

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.


2004 ◽  
Vol 127 (3) ◽  
pp. 590-597 ◽  
Author(s):  
Guo Xu ◽  
William W. Schultz ◽  
Elijah Kannatey-Asibu

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.


2020 ◽  
Vol 4 (4) ◽  
pp. 113
Author(s):  
Martin Lohse ◽  
Marcus Trautmann ◽  
Uwe Füssel ◽  
Sascha Rose

Gas metal arc welding torches are commonly chosen based on their current-carrying capacity. It is known that the current-carrying capacity of welding torches under CO2 is usually higher than under argon dominated shielding gases. In this publication, the extent to which this can be attributed to the shielding gas dependent arc radiation is investigated. For this purpose, the influence of the shielding gas on the thermal load of the shielding gas nozzle of a GMAW torch was calorimetrically measured. These experiments were carried out for four different shielding gases (argon, CO2, and two argon/CO2 mixtures). The measurements were all performed at an average current of 300 A. The welding current was set by adjusting the wire feed rate or the voltage correction. For each case, a separate set of experiments was done. It is shown that the changed arc radiation resulting from the different shielding gases has an influence on the heat input into the gas nozzle, and thus into the torch. For the same shielding gas, this influence largely correlates with the welding voltage.


Author(s):  
C D Yoo ◽  
Y S Yoo ◽  
H-K Sunwoo

The arc length has been detected through the arc because the welding current and voltage vary linearly with the arc length. In this work, the relationship between the arc light intensity and arc length is investigated through analytic modelling. The arc light intensity is derived as a function of the arc length and welding current using the heat balance in the plasma. Experiments are carried out to verify the proposed model and to find out the effects of welding conditions on the arc light intensity in gas metal arc welding (GMAW). The arc light intensity varies proportionally to the arc length and signal quality is enhanced with a fast weaving speed. The predicted results of the arc light intensity show reasonably good agreement with the experimental data.


2011 ◽  
Vol 339 ◽  
pp. 440-443 ◽  
Author(s):  
Shu Jun Chen ◽  
Chang Hui Liu ◽  
Yang Yu ◽  
Shao Jun Bai

This study proposed preset pulsed magnetic field acting on process of the short circuiting transfer. It is a controlled horizontal magnetic field which attached at the very beginning of contact between the wire and the weld pool during welding. It was found that there exists optimum conditions of magnetic field with which preset pulsed magnetic field could accelerate the rupture of the liquid bridge and reduce the peak value of welding current in the period of short circuiting transfer. This lead to energy accumulation lowered at the last phase of the short circuiting transfer and spatter loss reduced resulting from explosive short circuit rupture, in the meantime, it could improve the regularity and stability of the short circuiting transfer as well as the weld shaping quality.


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