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

Author(s):  
Ming Zhu ◽  
Yu Shi ◽  
Ding Fan

Consumable double-electrode gas metal arc welding (consumable DE-GMAW) is the efficient improvement of DE-GMAW. Due to the variety of coupled arc and metal transfer behaviors, this paper applies static force balance theory to analyze the changes in the forces acting on the main and bypass droplets separately. For main torch, the bypass arc changes the forces affecting on the main droplet, and the main metal transfer becomes more desirable. For bypass torch, with direct current electrode negative (DCEN) polarity, the volume of droplet is big and not easily transfers to the weld pool. In order to improve the bypass metal transfer, a method has been proposed which adds CO2 to pure argon shielding gas to change the forces affecting on the bypass droplet. Then, the welding experiment is carried out to test the effectiveness of this method. It is found that bypass droplet transfers easily and the diameter of bypass droplet is decreased significantly. Also a good weld appearance is acquired.

2013 ◽  
Vol 395-396 ◽  
pp. 1110-1113
Author(s):  
Ming Zhu ◽  
Ding Fan ◽  
Yu Shi ◽  
Hai Zhou

Consumable double-electrode gas metal arc welding (consumable DE-GMAW) is a novel and high efficient welding method. According to the different polarity of two electrodes in consumable DE-GMAW, the metal transfer behaviors are analyzed by using the state force balance theory. For main torch with direct current electrode positive polarity, the arc root area is enlarged by bypass arc and increased electromagnetic force promotes main metal transfer. For bypass torch with direct current electrode negative polarity, the electromagnetic force does not work on the melting area. Only gravity force is major detaching force. The volume of bypass droplet is large and not easily detache to the weld pool.


Author(s):  
Y M Zhang ◽  
E Liguo

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.


2013 ◽  
Vol 651 ◽  
pp. 333-337 ◽  
Author(s):  
Guo Hong Ma ◽  
Yu Ming Zhang

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.


Author(s):  
Y Wu ◽  
R Kovacevic

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.


2019 ◽  
Author(s):  
Emad Uddin ◽  
Usman Iqbal ◽  
Nabeel Arif ◽  
Samiur Rehman Shah

2018 ◽  
Vol 789 ◽  
pp. 64-68
Author(s):  
Yustiasih Purwaningrum ◽  
Medilla Kusriyanto ◽  
Rudi Kurniawan ◽  
Okto Akbar Rizky

This paper presented the effect of DE-GMAW (Double electrode gas metal arc welding)resistance on mechanical and physical properties of aluminium alloywelded. DE-GMAWis amethodof welding process that use two electrode. A non consumable torch is added to bypass the current inorder to reduce the heat input. The variation resistance used were 15Ω, 30Ω and 45Ω. Universaltesting machine and Vickers microhardness were used to measured mechanical properties of weldmetals with respect to strength and hardness. The microstructure was investigated by microscopeoptic with 100 x magnification. The grain size of weld metals with resistance value 30Ω is finer than15Ω and 45Ω. Dye penetrant test shows DE-GMAW welding machine that made have goodperformance because it can produce welding joint without surface crack. The results show thatresistance values optimum to DE-GMAW welding on aluminium alloy 5051 with 4 mm thickness is30Ω. It can be seen from the tensile test that shows the highest tensile strength is found in the DEGMAWwelding with resistance values 30Ω.


2019 ◽  
Vol 38 ◽  
pp. 179-186 ◽  
Author(s):  
Jiangkang Huang ◽  
Wei Pan ◽  
Wenting Yang ◽  
Cheng Xue ◽  
Yu Shi ◽  
...  

2007 ◽  
Vol 129 (6) ◽  
pp. 991-999 ◽  
Author(s):  
Kehai Li ◽  
YuMing Zhang

Gas metal arc welding (GMAW) is the most widely used process for metal joining because of its high productivity and good quality, but analysis shows that the fundamental characteristic restricts conventional GMAW from further increasing the welding productivity. A novel GMAW process, refereed to as double-electrode GMAW or DE-GMAW, thus has been developed to make it possible to increase the melting current while the base metal current can still be controlled at a desired level. This fundamental change provides an effective method to allow manufacturers to use high melting currents to achieve high melting speed and low base metal heat input. A series of experiments have been conducted to uncover the basic characteristics of this novel process. Results obtained from analyses of high-speed image sequences and recorded current signals suggest that DE-GMAW can lower the critical current for achieving the desired spray transfer, shift the droplet trajectory, reduce the diameter of the droplet, and increase the speed and (generation) rate of the droplets.


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