Numerical simulation for dynamic behavior of molten pool in tungsten inert gas welding with reserved gap

Hao, Haochen; Gao, J.; Huang, Haoshuo

doi:10.1016/j.jmapro.2020.07.063

Cited by 16 publications

(8 citation statements)

References 13 publications

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“…In contrast, when welding upward (C6-C8), the molten material moves towards the rear part of the melt pool because of the gravitational force, forming a concavity in the front part of the pool. The formation of this concavity increases the average arc length beneath the welding torch and the distribution parameter σ q (27). This increase in the distribution parameter reduces the temperature gradients over the melt pool surface and thus the magnitude of Marangoni forces.…”

Section: Discussionmentioning

confidence: 98%

“…Although many numerical models are available (e.g. [20][21][22][23][24][25][26][27]), numerical studies on melt-pool surface oscillations are scarce and the melt-pool oscillatory behaviour is not yet fully understood, particularly for positional welding conditions. Previous studies often focused on the influence of surface deformations on the melt-pool shape [28][29][30][31][32] or the morphology of the melt-pool surface, to study ripple formation [33], welding defects such as undercut [34] or humping [35][36][37].…”

Section: Introductionmentioning

confidence: 99%

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The effects of process parameters on melt-pool oscillatory behaviour in gas tungsten arc welding

Ebrahimi

Kleijn

Hermans

et al. 2021

J. Phys. D: Appl. Phys.

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Internal flow behaviour and melt-pool surface oscillations during arc welding are complex and not yet fully understood. In the present work, high-fidelity numerical simulations are employed to describe the effects of welding position, sulphur concentration (60-300 ppm) and travel speed (1.25-5 mm s −1 ) on molten metal flow dynamics in fully-penetrated melt-pools. A wavelet transform is implemented to obtain time-resolved frequency spectra of the oscillation signals, which overcomes the shortcomings of the Fourier transform in rendering time resolution of the frequency spectra. Comparing the results of the present numerical calculations with available analytical and experimental datasets, the robustness of the proposed approach in predicting melt-pool oscillations is demonstrated. The results reveal that changes in the surface morphology of the pool resulting from a change in welding position alter the spatial distribution of arc forces and power-density applied to the molten material, and in turn affect flow patterns in the pool. Under similar welding conditions, changing the sulphur concentration affects the Marangoni flow pattern, and increasing the travel speed decreases the size of the pool and increases the offset between top and bottom melt-pool surfaces, affecting the flow structures (vortex formation) on the surface. Variations in the internal flow pattern affect the evolution of melt-pool shape and its surface oscillations.

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Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

The effects of process parameters on melt-pool oscillatory behaviour in gas tungsten arc welding

Ebrahimi

Kleijn

Hermans

et al. 2021

J. Phys. D: Appl. Phys.

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“…Hao et al established a three-dimensional transient numerical analysis model of tungsten inert gas (TIG) welding with a reserved gap, and analyzed the dynamic variations in the flow field and deformation in the weld pool. Their findings indicated that the liquid metal flowed from both sides to the middle, bringing heat into the gap, and the liquid metal in front of the weld pool flowed to the back of the weld pool through the gap, increasing the weld penetration [ 7 ]. Li et al investigated variable narrow gap welding by rotating GMAW, and developed effective algorithms to extract the weld groove features [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Butt Gap on Stress Distribution and Carrying Capacity of X80 Pipeline Girth Weld

Zhu

Jia²,

et al. 2022

Materials

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An unstable assembly gap is detrimental to the formation and performance of the pipeline butt girth weld joint. Therefore, a numerical model of an 18.4 mm-thick X80 pipeline girth weld by a homogeneous body heat source was established to investigate the effect of the butt gap on the joint temperature and stress field, and carrying capacity. The accuracy of the simulation results was verified by measuring the welding thermal cycle with a thermocouple. The investigation results showed that the weld pool, heat-affected zone (HAZ) width, and maximum circumferential stress of the joint rose with the increase in the butt gap. The tensile stress unfavorable to the joint quality was mainly distributed in the weld metal and partial HAZ, and the distribution areas gradually expanded as the gap increased. The Von Mises stress peak value of the joint appeared in the order of 3 mm > 2 mm > 1 mm > 0 mm gap, reaching the maximum of 467.3 MPa (3 mm gap). This variation trend is directly related to the improvement in welding heat input with increasing butt gaps. The maximum Von Mises stress of the joint was positively correlated with the carrying capacity of the pipeline, which diminished as the butt gap enlarged. The pipeline carrying capacity reached 17.8 MPa for the joint with no butt gap, and dropped to 13.1 MPa for the joint with a 3 mm gap. The relationship between the carrying capacity (P) and butt gap (C) was described by P = −0.125C2 − 1.135C + 17.715, through which the pipeline carrying capacity with other butt gaps can be predicted.

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“…Jeong et al [26] proposed a separate heat source to simulate the molten pool flow in lap joint GTA welding. Hao et al [27] proposed a similar model to simulate TIG welding with a reserved gap. Cho et al [28] discussed the model setups for more realistic modeling results of one pulse one drop GMA welding.…”

Section: Introductionmentioning

confidence: 99%

Molten Pool Behaviors in Double-Sided Pulsed GMAW of T-Joint: A Numerical Study

Zhang

Wang

Lin

2021

Metals

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The T-joint is one of the essential types of joints in aluminum welded structures. Double-sided welding is a preferable solution to maintain high efficiency and avoid significant distortion during T-joint welding. However, interactions between double-sided molten pools make flow behaviors complicated during welding. Numerical simulations regarding molten pool behaviors were conducted in this research to understand the complex flow phenomenon. The influences of wire feed rates and torch distances were simulated and discussed. The results show that droplet impinging drives the fluid to flow down to the root and form a frontward vortex. Marangoni stress forces the fluid to form an outward vortex near the molten pool boundary and flatten the concave-shaped molten pool surface. With an increased wire feed speed, the volume of the molten pool increases, and the root fusion is improved. With an increased torch distance, the width of the front molten pool decreases while the length increases, and the rear molten pool size decreases slightly. Both wire feed speeds and the torch distances have limited influences on the basic flow characteristics.

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Numerical simulation for dynamic behavior of molten pool in tungsten inert gas welding with reserved gap

Cited by 16 publications

References 13 publications

The effects of process parameters on melt-pool oscillatory behaviour in gas tungsten arc welding

The effects of process parameters on melt-pool oscillatory behaviour in gas tungsten arc welding

Effect of Butt Gap on Stress Distribution and Carrying Capacity of X80 Pipeline Girth Weld

Molten Pool Behaviors in Double-Sided Pulsed GMAW of T-Joint: A Numerical Study

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