Analysis of Metal Transfer and Weld Forming Characteristics in Triple-wire Gas Indirect Arc Welding

Abstract Triple-wire gas indirect arc welding (TW-GIA) has the advantages of low heat input and high deposition rate. However, the simultaneous melting of triple wires makes the metal transfer mode complicated. The unknown of the metal transfer mode restricts the development of this technology. In this paper, high-speed camera systems and electrical signal acquisition sensors were used to explore the TW-GIA metal transfer mode. The static force model and the arc conductive channel model were used to discuss the droplet force and energy conversion characteristics respectively. Results showed that the TW-GIA metal transfer modes can be divided into: short-circuit transfer (SCT), main wire projected transfer + side wire globular transfer (PGT), main wire streaming transfer + side wire projected transfer (SPT) and main wire streaming transfer + side wire streaming transfer (SST). Moreover, the process parameter ranges corresponding to the four modes were summarized. Due to the stable arc and the uniform metal transfer process, SPT and SST can form desirable weld seam. The gravity and z-axis components of electromagnetic force are the main forces that promote metal transfer. The x-axis and y-axis components of the electromagnetic force deviate the metal transfer path from the arc coverage. Due to the change of arc conductive channel, the energy transferred from TW-GIA to the base metal is less than that of GMAW, showing the advantages of small welding deformation, narrow heat affected zone and grain refinement.

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Effects of Welding Current on Metal Transfer and Weld Pool Dynamics in Gas Metal Arc Welding

Heat Transfer, Volume 2 ◽

10.1115/imece2006-15617 ◽

2006 ◽

Author(s):

J. Hu ◽

H. L. Tsai ◽

P. C. Wang

Keyword(s):

Weld Pool ◽

Arc Welding ◽

Gma Welding ◽

Gas Metal Arc Welding ◽

Metal Transfer ◽

Dominant Factor ◽

Transient Temperature ◽

Transfer Mode ◽

Metal Arc Welding ◽

Metal Transfer Mode

In gas metal arc welding (GMAW), current is one of the most important factors affecting the mode of metal transfer and subsequently the weld quality. Recently, a new technology using pulsed currents has been employed to achieve the one droplet per pulse (ODPP) metal transfer mode with the advantages of low average currents, a stable and controllable droplet generation, and reduced spatter. In this paper, the comprehensive model recently developed by the authors was used to study the influences of different current profiles on the droplet formation, metal transfer, and weld pool dynamics in GMA, welding. Five types of welding currents were studied, including two constant currents and three waveform currents. In each type, the transient temperature and velocity distributions of the arc plasma and the molten metal, and the shapes of the droplet and the weld pool were calculated. The results showed that a higher electromagnetic force was generated at a higher current and becomes the dominant factor that detaches the droplet from the electrode tip. A smaller droplet size and a higher droplet frequency were obtained for a higher current. The model has demonstrated that a stable ODPP metal transfer mode can be achieved by choosing a current with proper waveform for given welding conditions.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.766 ◽

2011 ◽

Vol 189-193 ◽

pp. 766-770 ◽

Cited By ~ 1

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.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.297-300.2825 ◽

2005 ◽

Vol 297-300 ◽

pp. 2825-2830 ◽

Cited By ~ 4

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.

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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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