scholarly journals Interactive Phenomena in Hybrid KPAW–GMAW-P

2020 ◽  
Vol 99 (05) ◽  
pp. 146s-155s
Author(s):  
DONGSHENG WU ◽  
◽  
SHINICHI TASHIRO ◽  
ZIANG WU ◽  
MANABU TANAKA ◽  
...  
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Video Camera ◽  
Plasma Arc ◽  
Tungsten Electrode ◽  
Current Path ◽  
Metal Arc Welding ◽  
High Speed Video Camera

A hybrid welding technique formed by combining keyhole plasma arc welding (KPAW) and pulsed gas metal arc welding (GMAW-P) is characterized by the complex interactions of the arc, droplet, keyhole, and weld pool. With the help of a high-speed video camera, zirconia particles, and a thermal camera, the complex interactive phenomena of the hybrid KPAW–GMAW-P process was analyzed. Owing to the formation of a direct-current path between the KPAW cathode (tungsten electrode) and the GMAW anode (welding wire), the ionized plasma arc was extended to the GMA side, causing an expansion of the GMA. The current at the GMAW droplet was diverged; thus, the Lorentz force promoted a more stable one pulse one droplet metal transfer mode compared with that of GMAW-P. The strong backward flow from the keyhole was suppressed because of the pull-push flow pattern on the top surface of the weld pool be-tween the two arcs. As the heat and molten metal in the weld pool were transported from the region near the GMA (high temperature) to the region near the plasma arc (low temperature), the weld pool temperature decreased.

Behavior of Exit Keyhole Diameter during Switch off Period in Plasma Keyhole Arc Welding

2018 ◽  
Vol 26 ◽  
pp. 87-92
Author(s):  
Anh Nguyen Van ◽  
Tashiro Shinichi ◽  
Huu Manh Ngo ◽  
Akihisa Murata ◽  
Tadasuke Murata ◽  
...  
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
High Speed ◽  
Video Camera ◽  
High Speed Video ◽  
High Speed Video Camera

The purpose of this investigation is to clarify the behavior of exit keyhole diameter during switch off (cutting arc) period in case of Plasma keyhole arc welding (PKAW). During switch off period, the keyhole and weld pool are visualized from backside via a high speed video camera (HSVC). The result showed that keyhole diameter on the backside is unstable. The keyhole size is much changed in X-axis. Firstly, it is increased and then it is decreased to a stationary value at t = 0.05 s after cutting arc. Meanwhile, the size in Y-axis is not changed approximately from t = 0.01 s after cutting arc. The results can be considered to control this process more efficiency.

Modeling of Three-Dimensional Gas Metal Arc Welding With Groove

2007 ◽  
Author(s):  
J. Hu ◽  
H. L. Tsai
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Filler Metal ◽  
Gas Metal Arc Welding ◽  
Three Dimensional ◽  
Plasma Arc ◽  
Droplet Impingement ◽  
Sulfur Species ◽  
Metal Arc Welding ◽  
Arc Pressure

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.

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.

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.

Metal Transfer in Double-Electrode Gas Metal Arc Welding

2007 ◽  
Vol 129 (6) ◽  
pp. 991-999 ◽  
Author(s):  
Kehai Li ◽  
YuMing Zhang
Keyword(s):  
Base Metal ◽  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
High Melting ◽  
High Productivity ◽  
Spray Transfer ◽  
Metal Arc Welding ◽  
Double Electrode ◽  
Melting Current

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.

An Evaluation System of Pulsed GMAW Process

2013 ◽  
Vol 483 ◽  
pp. 599-602
Author(s):  
Ying Gao ◽  
Jing Hua Han ◽  
Li Yan Lou ◽  
Huan Li
Keyword(s):  
Arc Welding ◽  
Evaluation System ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Electric Signal ◽  
Characteristic Parameters ◽  
Display Module ◽  
Metal Arc Welding ◽  
Labview Platform

A process evaluation system for pulsed gas metal arc welding (GMAW-P) based on the LabVIEW platform has been developed. This system is comprised of two modules, a simultaneous display module and a data analysis module. Using these modules, the system can not only provide a comprehensive direct viewing display of the welding electric signal and high speed camera photo, but also can analyze the characteristic parameters of the welding process. The results show that the system works properly.

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