Investigation of molten pool oscillation during GMAW-P process based on a 3D model

Wang, L L; Lu, Fenggui; Cui, Haichao; Tang, Xiaoying

doi:10.1088/0022-3727/47/46/465204

Cited by 9 publications

(5 citation statements)

References 21 publications

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“…Moreover, the greater driving forces have the ability to propel a more intense convection in the weld pool. As simulated by Wang et al [16], the arc pressure increases significantly with the current augmented, and the arc pressure for the peak current, 220 A, is almost six times higher than that at base current of 90 A. Because of the dominant role played by arc pressure in depressing the weld pool surface, the greater arc pressure will no doubt cause a deeper weld pool surface deformation, which may affect the reinforcement height in two ways: (1) The deeper weld pool surface, combined with the larger weld pool, lowers the whole reinforcement height; and (2) the reinforcement maintains low height when it solidifies at the rear part of the weld pool, which highlights the liquid flow driven by the droplet impingement.…”

Section: W-shaped Reinforcementmentioning

confidence: 88%

“…Thus, the heat brought by the arc can be more easily transferred to the base metal in a solid state, which will be melted faster. Moreover, Wang et al [16] indicated that droplets with abundant heat would impinge into the weld pool at high speed, which will easily pass through the thin liquid layer, crash against the solid bottom, and create a crater. The penetration is then deepened further, and when the average current reaches 104 A, the base metal is fully penetrated.…”

Section: Profile Map and Stages Of Weld Beadsmentioning

confidence: 99%

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Profile Map of Weld Beads and Its Formation Mechanism in Gas Metal Arc Welding

Zhang

Xue

2019

Metals

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In order to investigate the profile map of weld beads and its formation mechanism in gas metal arc welding (GMAW), bead-on-plate welding was carried out with different average currents, and the dimensions of a weld bead were measured. The results show that the profile of weld beads can be divided into three stages according to the volume relationship between the melted filler metal and the weld pool. During the stages, the top surface of the reinforcement consisting of the central plane and the side plane mainly goes through inversed-U, W, V, and U shapes, which are mainly attributed to the change of flow pattern. Moreover, the role played by the bottom wall in determining the flow pattern and the resultant bead profile has been investigated as well. The experiment results show that with the bottom wall changing from the solid to the totally melted state, the role of redirecting, redistributing and bearing the molten metal played by the bottom wall gradually disappears. As a result, the side reinforcement is no longer covered by the liquid flowing backward. The top reinforcement is thoroughly collapsed when the width of the bottom reinforcement exceeds that of the top one by 1.1 mm.

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Section: W-shaped Reinforcementmentioning

confidence: 88%

Section: Profile Map and Stages Of Weld Beadsmentioning

confidence: 99%

Profile Map of Weld Beads and Its Formation Mechanism in Gas Metal Arc Welding

Zhang

Xue

2019

Metals

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“…The remarkable surface depression caused by arc pressure following a Gaussian distribution thinned the fluid layer between the arc and solid base metal [20], thus decreasing the buffering of the weld puddle from the droplet impact [4,21]. The acceleration of the droplets due to the plasma drag force [6], combined with the weakened buffering effect of the weld puddle, made it easier for droplets to reach the bottom boundary of the weld pool, even with substantial redundant momentum.…”

Section: Welding Torch Perpendicular To the Base Metalmentioning

confidence: 99%

Effect of Droplet Impingement on the Weld Profile and Grain Morphology in the Welding of Aluminum Alloys

et al. 2018

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To achieve a better understanding of the effect of droplet impingement on the weld profile and grain morphology, welding with vertical and inclined torches in the double pulsed-gas metal arc welding of aluminum alloy were compared. When using vertical welding, the grains along the wall of the finger-like penetration (FLP) were refined by a more violent flow driven by droplet impingement running in the confined space created by FLP. When using inclined welding, the sharp inflection point disappeared and the curved columnar grains emerged on the non-impact action side, which was attributed to the gradually weakened impingement at that location. Moreover, when the penetration became shallower due to a low mean current, the droplets impinged alternately along split trajectories, causing significant changes in the grain morphology, such as creating grains which were sharply shortened by the direct impact of droplet impingement at impact point. The change of trajectory was ascribed to the variation of the width/depth ratio of FLP, which changed the magnitude of the contradiction between the room required by the fluid flow driven by droplet impingement and the space supplied for that by FLP.

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“…In order to simplify the mathematical model formulation, the following assumptions were made: Fluctuations of the welding arc burning due to electrode melting and droplets detachments are neglected; the hydrodynamic flow is Newtonian, in-compressible and laminar, the Boussinesq buoyancy approximation is applied; the initial droplet velocity, temperature and diameter in dependence on welding parameters are calculated by given empirical equations. The developed approach to speed up the calculation, was based on an idea that was proposed earlier [4,5]. It is supposed that the incoming droplet is considered as a non-mixed particle that keeps its mass and size.…”

Section: Description Of the Mathematical Modelmentioning

confidence: 99%

Numerical investigation of droplet impact on the welding pool in gas metal arc welding

Mokrov

Lysnyi

Simon

et al. 2017

Materialwissenschaft Werkst

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A transient three-dimensional model that describes physical phenomena inside a welding pool during gas-metal arc welding process is presented. The model considers such phenomena as heat-mass transfer, electromagnetics, hydrodynamic processes and deformation of the weld pool free surface. The fluid flow in the weld pool is induced due to the presence of the mechanical impact of the droplets, thermo-capillary surface tension, thermal buoyancy and electromagnetic forces. The weld pool surface deformation is calculated by considering arc pressure and droplet impact force. A comparative analysis of the impact of the electric current of the welding arc and different force factors causing the motion of liquid metal in the weld pool on the shape of the welded seam was carried out and discussed. Keywords: Arc welding / numerical simulation / hydrodynamics / welded seam formation / droplet impact Es wird ein transientes, dreidimensionales Modell vorgestellt, das die physikalischen Phä nomene in einem Schmelzbad beim Metallschutzgasschweißen beschreibt. Das Modell berü cksichtigt solche Phä nomene wie Wä rme-und Massenü bertragung, elektromagnetische Phä nomene, hydrodynamische Prozesse und die Deformierung der freien Schmelzbadoberflä che. Die Strö mungen im Schmelzbad werden hervorgerufen durch den mechanischen Aufprall der Tropfen, die thermokapillare Oberflä chenspannung, den thermischen Auftrieb und elektromagnetische Krä fte. Bei der Berechnung der Deformation der Schmelzbadoberflä che werden der Lichtbogendruck und die Kraft der auftreffenden Tropfen berü cksichtigt. Eine vergleichende Analyse des Einflusses des elektrischen Stromes des Schweißlichtbogens und der verschiedenen Krä fte, die die Bewegung des flü ssigen Metalls im Schmelzbad verursachen, auf die Form der Schweißnaht wurde durchgefü hrt und diskutiert. Schlü sselwö rter: Lichtbogenschweißen / numerische Simulation / Strö mungen / Schweißnahtbildung / Tropfenwirkung

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Investigation of molten pool oscillation during GMAW-P process based on a 3D model

Cited by 9 publications

References 21 publications

Profile Map of Weld Beads and Its Formation Mechanism in Gas Metal Arc Welding

Profile Map of Weld Beads and Its Formation Mechanism in Gas Metal Arc Welding

Effect of Droplet Impingement on the Weld Profile and Grain Morphology in the Welding of Aluminum Alloys

Numerical investigation of droplet impact on the welding pool in gas metal arc welding

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