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

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.

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Mechanically assisted droplet transfer process in gas metal arc welding

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1243/0954405021520247 ◽

2002 ◽

Vol 216 (4) ◽

pp. 555-564 ◽

Cited By ~ 19

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.

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Analytical Modeling of Metal Transfer for GMAW in the Globular Mode

ASME 2008 International Manufacturing Science and Engineering Conference, Volume 1 ◽

10.1115/msec_icmp2008-72548 ◽

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.

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Numerical analysis of the dynamic growth of droplets in gas metal arc welding

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406001523245 ◽

2000 ◽

Vol 214 (10) ◽

pp. 1247-1258 ◽

Cited By ~ 5

Author(s):

Y M Zhang ◽

E Liguo

Keyword(s):

Feedback Control ◽

Transfer Process ◽

Arc Welding ◽

Gas Metal Arc Welding ◽

Surface Tension Force ◽

Metal Transfer ◽

Force Balance ◽

Droplet Growth ◽

Metal Arc Welding ◽

Control Technologies

Feedback control of droplet transfer is pursued as a solution to produce sound welds in gas metal arc welding. In previous work, a real-time visual system has been developed to monitor on line the droplet size and geometry. To realize feedback control of metal transfer, this study addresses the dynamic process of droplet growth and detachment. The droplet is subjected to gravitational force, electromagnetic force, plasma drag force and surface tension force. The geometry of the droplet is determined by these forces through the static force balance. However, the forces acting on the droplet continuously change as the melting electrode wire changes the droplet geometry. Because of this interdependence between the droplet geometry and the forces, the model must be solved dynamically and iteratively. A numerical program has been developed to acquire its dynamic numerical solution. Hence, the dynamics of the metal transfer process can be understood and simulated. Currently, this model is being used to simulate theclosed-loop controlled metal transfer process using different advanced control technologies.

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Globular-to-Spray Transition in Cold Wire Gas Metal Arc Welding

Welding Journal ◽

10.29391/2021.100.010 ◽

2021 ◽

Vol 100 (4) ◽

pp. 121-131

Author(s):

R. A. RIBEIRO ◽

◽

P. D. C. ASSUNÇÃO ◽

E. B. F. DOS SANTOS ◽

E. M. BRAGA ◽

...

Keyword(s):

Arc Welding ◽

High Speed ◽

Gas Metal Arc Welding ◽

Welding Current ◽

Electrical Current ◽

Feed Speed ◽

High Speed Imaging ◽

Transition Mechanism ◽

Cold Wire ◽

Metal Arc Welding

The electrical current required for a transition from globular to spray droplet transfer during gas metal arc welding (GMAW) is determined by the specified wire feed speed in the case of constant-voltage power supplies. Generally, in narrow groove welding, spray transfer is avoided, be-cause this transfer mode can severely erode the groove sidewalls. This work compared the globular-to-spray transition mechanism in cold wire gas metal arc welding (CW-GMAW) vs. standard GMAW. Synchronized high-speed imaging with current and voltage samplings were used to characterize the arc dynamics for different cold wire mass feed rates. Subsequently, the droplet frequency and diameter were estimated, and the parameters for a globular-to-spray transition were assessed. The results suggest that the transition to spray occurs in CW-GMAW at a lower current than in the standard GMAW process. The reason for this difference appears to be linked to an enhanced magnetic pinch force, which is mainly responsible for metal transfer in higher welding current conditions.

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Analytical Modeling of Metal Transfer for GMAW in the Globular Mode

Journal of Manufacturing Science and Engineering ◽

10.1115/1.3006317 ◽

2008 ◽

Vol 130 (6) ◽

Cited By ~ 5

Author(s):

U. Ersoy ◽

E. Kannatey-Asibu ◽

S. J. Hu

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 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. Possible regions of unstable metal transfer are investigated both by the model and experiments. The model can be used to identify the range of welding wire feed rates that results in stable metal transfer during the globular mode of metal transfer.

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Gas Metal Arc Welding Modes in Wire Arc Additive Manufacturing of Ti-6Al-4V

Materials ◽

10.3390/ma14092457 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2457

Author(s):

Oleg Panchenko ◽

Dmitry Kurushkin ◽

Fedor Isupov ◽

Anton Naumov ◽

Ivan Kladov ◽

...

Keyword(s):

Additive Manufacturing ◽

Arc Welding ◽

High Speed ◽

Gas Metal Arc Welding ◽

Metal Transfer ◽

Process Data ◽

Cold Metal Transfer ◽

Wall Width ◽

Metal Arc Welding ◽

Wire Arc Additive Manufacturing

In wire arc additive manufacturing of Ti-alloy parts (Ti-WAAM) gas metal arc welding (GMAW) can be applied for complex parts printing. However, due to the specific properties of Ti, GMAW of Ti-alloys is complicated. In this work, three different types of metal transfer modes during Ti-WAAM were investigated: Cold Metal Transfer, controlled short circuiting metal transfer, and self-regulated metal transfer at a direct current with a negative electrode. Metal transfer modes were studied using captured waveform and high-speed video analysis. Using these modes, three walls were manufactured; the geometry preservation stability was estimated and compared using effective wall width calculation, the microstructure was analyzed using optical microscopy. Transfer process data showed that arc wandering depends not only on cathode spot instabilities, but also on anode processing properties. Microstructure analysis showed that each produced wall consists of phases and structures inherent for Ti-WAAM. α-basketweave in the center of and α-colony on the grain boundary of epitaxially grown β-grains were found with heat affected zone bands along the height of the walls, so that the microstructure did not depend on metal transfer dramatically. However, the geometry preservation stability was higher in the wall, produced with controlled short circuiting metal transfer.

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Modeling of Metal Transfer in Short Circuiting Arc Welding

Manufacturing Engineering and Materials Handling Engineering ◽

10.1115/imece2004-59147 ◽

2004 ◽

Cited By ~ 1

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.

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A Way to Weld Sheet Metal with Double-Electrode GMAW

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.651.333 ◽

2013 ◽

Vol 651 ◽

pp. 333-337 ◽

Cited By ~ 1

Author(s):

Guo Hong Ma ◽

Yu Ming Zhang

Keyword(s):

Arc Welding ◽

High Speed ◽

Gas Metal Arc Welding ◽

Metal Transfer ◽

Constant Current ◽

Spray Transfer ◽

Metal Arc Welding ◽

Globular Transfer ◽

Double Electrode ◽

Welding System

This paper designed a double-electrode GMAW(gas metal arc welding) system. This system includes main arc and bypass arc. Main arc (Base metal current: Ibm) is supplied with Constant Current power (CC mode) and bypass arc (bypass current: Ibp) is Constant Voltage power (CV mode). Main arc electrode used common carbon wire, bypass arc electrode used water cool copper. Welding experiment shows this DE-GMAW can change common metal transfer into spray transfer with lowest critical total current (Itotal) 200 amps. When Ibm decreases and bypass voltage increases, this critical current will increase and it is less than 230 amps when keeping spray transfer. High speed video proved that metal transfer is changed from spray transfer to globular transfer.

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