Numerical Coupling Analysis of Droplets’ Behaviors in GMAW

2010 ◽  
Vol 139-141 ◽  
pp. 981-985
Author(s):  
Yan Lu Huang ◽  
Xin You Ke ◽  
Yi Bin Li
Keyword(s):  
Electric Current ◽  
Current Density ◽  
Electromagnetic Force ◽  
Electromagnetic Coupling ◽  
Gas Metal Arc Welding ◽  
Coupling Model ◽  
Metal Transfer ◽  
Electric Current Density ◽  
Forming Process ◽  
Metal Arc Welding

The forming process and dynamic behaviors of droplets in gas metal arc welding (GMAW) were numerically simulated by using weak electromagnetic coupling method, with considering the gravity, the electromagnetic force, the free surface and the turbulent flow in the droplets. The shape update of the droplets was calculated on basis of VOF and CSF theories. The Gaussian electric current density was identified as boundary conditions for calculating electromagnetic force. A weak electromagnetic coupling model was used to study the characteristics of relevant physical variables and their roles in metal transfer. The simulation results suggest that the maximal value of electric current density lies in the neck of droplets, and the electromagnetic force has great effects of accelerating droplets’ contraction and shortening their falling time. Under the action of strong electromagnetic force, the metal transfer is in a spray form rather than a globular one in GMAW process. The simulated results agree well with theoretical analyses and predecessors’ experiments.

Study on the Incline Limit in Gas Metal Arc Welding Based Rapid Forming

2011 ◽  
Vol 189-193 ◽  
pp. 766-770 ◽  
Author(s):  
Feng Liang Yin ◽  
Sheng Zhu ◽  
Jian Liu ◽  
Qi Wei Wang
Keyword(s):  
Welding Speed ◽  
Arc Welding ◽  
Short Circuit ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Forming Process ◽  
Transfer Mode ◽  
Metal Arc Welding ◽  
Supporting Material ◽  
Metal Transfer Mode

The paper defined a concept of the utmost shapeable angle for the gas metal arc welding based rapid forming process, which is used to judge supporting material need to be employed or not when a inclined wall is deposited. If the angle formed by the outer normal of the inclined wall and building direction exceeds the sum of the utmost shapeable angle and π/2, then supporting material must be deposited to finish the inclined wall along the given building direction. The effects of metal transfer mode and welding speed on the utmost shapeable angle were studied. It is found that the ‘one droplet per pulse’ metal transfer mode in pulse-current welding based RP may obtain a bigger utmost shapeable angle than short circuit metal transfer mode does. The welding speed influences the utmost shapeable angle through heat input and bead profile. An abrupt bead is harmful to get a bigger utmost shapeable angle. Within a welding speed extension from 9 mm/s to 30 mm/s, the utmost shapeable angle gets the maximum value of 55° when the welding speed is 18 mm/s.

The Effect of External Electromagnetic Force in Gas Metal Arc Welding on the Transfer Mode

2005 ◽  
Vol 297-300 ◽  
pp. 2825-2830 ◽  
Author(s):  
S.H. Lee ◽  
J.S. Kim ◽  
Bo Young Lee ◽  
Sang Yul Lee
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Force ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Generation Rate ◽  
Electromagnetic Current ◽  
Transfer Mode ◽  
Metal Arc Welding ◽  
Co2 Welding

In Gas Metal Arc Welding (GMAW), electromagnetic force is one of the most important factors that effects the metal transfer, short-circuit rate, spatter generation rate and mechanical properties for welding metal. Shielding gas and welding current have a great influence on metal transfer mode in GMAW. In this paper different ways for external electromagnetic forces are applied by attaching a cylindrically rounded conducting wire solenoid on touch tip holding. It was conformed that the intensities of electromagnetic force and kinds of shielding gases influence on the droplet transfer mode. With the applied electromagnetic field, the arc transfer mode changes from normal mode to rotating mode. The rotating direction changes with the change of electromagnetic current direction. Applied electromagnetic field intensity varied by electromagnetic current influences on the spatter generation rate in CO2 welding. In MIG welding, the influences of electromagnetic force on the spatter generation showed different tendency as in the CO2 welding. This paper is for the purpose of discussing these factors.

scholarly journals The effect of simplifications of a numerical mesh on the results of electromagnetic analysis of the Nuclotron-type cable

2018 ◽  
Vol 177 ◽  
pp. 08004
Author(s):  
Łukasz Tomków
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Current Density ◽  
Electric Current Density ◽  
Electromagnetic Analysis ◽  
First Case ◽  
Single Region ◽  
The Magnetic Field

The model of a single Nuclotron-type cable is presented. The goal of this model is to assess the behaviour of the cable under different loads. Two meshes with different simplifications are applied. In the first case, the superconductor in the cable is modelled as single region. Second mesh considers individual strands of the cable. The significant differences between the distributions of the electric current density obtained with both models are observed. The magnetic field remains roughly similar.

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.

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