Numerical investigation of weld pool behaviors and ripple formation for a moving GTA welding under pulsed currents

Liu, J.W.; Rao, Zhenghua; Liao, Shengming; Tsai, Hai-Lung

doi:10.1016/j.ijheatmasstransfer.2015.08.046

Cited by 38 publications

(20 citation statements)

References 28 publications

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“…It was observed while welding of SAE-1020 material that when peak current was increased by keeping the same mean current, the width of the weld bead will increase and no effect on weld penetration. But when peak current was increased by decreasing the mean current it reduced the weld bead penetration but no change in weld bead width 42) . It is also found that when peak current is used at higher side it increases both weld bead ripple formation and penetration [42][43][44] .…”

Section: Effect Of Pulsed Parameters On Weld Bead Geometrymentioning

confidence: 91%

“…But when peak current was increased by decreasing the mean current it reduced the weld bead penetration but no change in weld bead width 42) . It is also found that when peak current is used at higher side it increases both weld bead ripple formation and penetration [42][43][44] . It is also observed that at extreme low and high frequency, peak current has less significance on aspect ratio (weld bead width to penetration ratio) 45) .…”

Section: Effect Of Pulsed Parameters On Weld Bead Geometrymentioning

confidence: 91%

“…As in case of pulsed current welding, the peak current along with background current, frequency and duty cycle influences the heat input and hence microstructure. In double pulsed welding it is found that the value of peak current should be optimum to achieve finer grain for T-joint welding 53) . Lower duty cycle results in finer microstructure due to large time available for cooling 50) .…”

Section: Effect Of Pulsed Parameters On Metallurgical Propertiesmentioning

confidence: 99%

See 2 more Smart Citations

A Review on Twin Tungsten Inert Gas Welding Process Accompanied by Hot Wire Pulsed Power Source

Shah

Agrawal

2019

Journal of Welding and Joining

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Tungsten Inert Gas (TIG) welding process is used in the industry due to its positional suitability, good control over metallurgical and mechanical properties and weld integrity. It makes this process more suitable to weld the root pass in the piping industries. However, there is a remarkable limitation to increase the welding current beyond a certain limit in the conventional TIG welding process due to limited current carrying capacity of a single electrode and higher arc pressure. This limits its productivity. To combat it, Twin TIG (T-TIG) welding process is introduced where the two tungsten electrodes are present in one torch. The two separate and synchronized power sources are connected to the two electrodes. To increase the metal deposition rate, the hot filler wire is used because it reduces the requirement of heat from arc plasma. There is another advancement in the TIG welding process which incorporates pulsed power source assisted welding process to control weld bead geometry, microstructure and to weld dissimilar material. This paper presents the effect of parameters of T-TIG, hot wire, and pulsed current welding processes when performed separately. A novel welding set up is proposed to weld dissimilar material with weld integrity. This paper suggests that when these three techniques are used simultaneously by meticulous studies of their process parameters with automation, an outperformed technique can be evolved which multiples the individual advantages of the three processes.

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Section: Effect Of Pulsed Parameters On Weld Bead Geometrymentioning

confidence: 91%

Section: Effect Of Pulsed Parameters On Weld Bead Geometrymentioning

confidence: 91%

Section: Effect Of Pulsed Parameters On Metallurgical Propertiesmentioning

confidence: 99%

See 1 more Smart Citation

A Review on Twin Tungsten Inert Gas Welding Process Accompanied by Hot Wire Pulsed Power Source

Shah

Agrawal

2019

Journal of Welding and Joining

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“…In contrast, the separated model is a more economical choice if the molten pool is of more interest in the simulation. In separated models, the free surface of the molten pool needs to be calculated through profile equilibrium method [21], VOF method [22][23][24][25][26][27], or Level-set method [28]. Empirical Gaussian distributions of heat flux and current density are often used on the free surface.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of heat transfer and fluid flow in multilayer deposition of PAW-based wire and arc additive manufacturing

Bai

Colegrove

Ding

et al. 2018

International Journal of Heat and Mass Transfer

195

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A three-dimensional numerical model has been developed to investigate the fluid flow and heat transfer behaviors in multilayer deposition of plasma arc welding (PAW) based wire and arc additive manufacture (WAAM). The volume of fluid (VOF) and porosity enthalpy methods are employed to track the molten pool free surface and solidification front, respectively. A modified double ellipsoidal heat source model is utilized to ensure constant arc heat input in calculation in the case that molten pool surface dynamically changes. Transient simulations were conducted for the 1 st , 2 nd and 21 st layer depositions. The shape and size of deposited bead and weld pool were predicted and compared with experimental results. The results show that for each layer of deposition the Marangoni force plays the most important role in affecting fluid flow, conduction is the dominant method of heat dissipation compared to convection and radiation to the air. As the layer number increases, the length and width of molten pool and the width of deposited bead increase, whilst the layer height decreases. However these dimensions remain constant when the deposited part is sufficiently high. In high layer deposition, where side support is absent, the depth of the molten pool at the rear part is almost flat in the Y direction. The profile of the deposited bead is mainly determined by static pressure caused by gravity and surface tension pressure, therefore the bead profile is nearly circular. The simulated profiles and size dimensions of deposited bead and molten pool were validated with experimental weld appearance, cross-sectional images and process camera images. The simulated results are in good agreement with experimental results.

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“…Because of the asymmetric heat input, more base metal melted on the left side of the axial line of the welding wire than on the right side, causing the bottom to be uneven. Thus, when the droplet impacted the uneven bottom of the weld pool, the more molten region (in this case, the left side) had a considerably lower resistance to the impingement because of its liquid state than the solid-state region on the right side [11,26]. Thus, instead of impacting both sides at the same order of magnitude, as in case 1, the droplet impacted harder on the left side due to its weak resistance.…”

Section: Welding Torch Inclined In the Transverse Sectionmentioning

confidence: 91%

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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Numerical investigation of weld pool behaviors and ripple formation for a moving GTA welding under pulsed currents

Cited by 38 publications

References 28 publications

A Review on Twin Tungsten Inert Gas Welding Process Accompanied by Hot Wire Pulsed Power Source

A Review on Twin Tungsten Inert Gas Welding Process Accompanied by Hot Wire Pulsed Power Source

Numerical analysis of heat transfer and fluid flow in multilayer deposition of PAW-based wire and arc additive manufacturing

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

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