Effects of shielding gas compositions on arc plasma and metal transfer in gas metal arc welding

Rao, Zhenghua; Liao, Shengming; Tsai, Hai-Lung

doi:10.1063/1.3291121

Cited by 42 publications

(16 citation statements)

References 25 publications

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“…The physical properties of argon plasma are temperature-dependent (Murphy, 2013). The substrate and wire are mild steel, and the thermophysical properties of mild steel refer to the work of Rao et al (2010c).…”

Section: Boundary Conditionsmentioning

confidence: 99%

Investigation of the effect of torch tilt and external magnetic field on arc during overlapping deposition of wire arc additive manufacturing

Zhou

Tian

et al. 2020

RPJ

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Purpose The purpose of this paper is to find a theoretical reference to adjust the unsymmetrical arc shape and plasma flow of overlapping deposition in wire arc additive manufacturing (WAAM) and ensure the effect of the gas shielding and stable heat and mass transfer in deposition process. The multiphysical numerical simulation and physical experiment are used for validation. Design/methodology/approach In this study, welding torch tilt deposition and external parallel magnetic field–assisted deposition are presented to adjust the unsymmetrical arc shape and plasma flow of overlapping deposition, and a three-dimensional numerical model is developed to simulate the arc of torch tilt overlapping deposition and external parallel magnetic field–assisted overlapping deposition. Findings The comparison of simulated results indicate that the angle of welding torch tilt equal to 20° and the magnetic flux density of external transverse magnetic field equal to 0.001 Tesla are capable of balancing the electric arc and shielding gas effectively, respectively. The arc profiles captured by a high-speed camera match well with simulated results. Originality/value These studies of this paper can provide a theoretical basis and reference for the calibration and optimization of WAAM process parameters.

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Section: Boundary Conditionsmentioning

confidence: 99%

Investigation of the effect of torch tilt and external magnetic field on arc during overlapping deposition of wire arc additive manufacturing

Zhou

Tian

et al. 2020

RPJ

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“…This cylindrical feature does not extend fully to the anode and extends only slightly beyond the electrode, suggesting that a body force is acting heavily on the flow close to the anode. Based on numerical magneto-hydrodynamic models [24][25][26][27], the plasma jet is indeed expected to decelerate, as the axial Lorentz forces are expected to change magnitude and direction locally due to increased electromagnetic activity close to the anode. This observation is also supported by previous measurements which show that helium produces a lower arc stagnation pressure than argon [27].…”

Section: Pure Heliummentioning

confidence: 99%

Visualisation of alternating shielding gas flow in GTAW

Bitharas¹,

Campbell²,

Galloway³

et al. 2016

Materials & Design

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The alternating shielding gas technique is a method of achieving transient arc characteristics during arc welding; however the complex flow that occurs through its use has not been investigated previously. A schlieren system was used to image density gradients that arise when alternating argon and helium shield gases, under varying flow parameters, with gas tungsten arc welding (GTAW). A theoretical analysis was carried out to determine the conditions under which the technique facilitates arc pulsing, in particular to avoid mixing the shield gases in the delivery pipe prior to the welding nozzle. At appropriate pulsing frequency and flow rates, a stable horizontal region of helium was obseved in the weld region, maintained in position by the denser argon from the preceding pulse. This higher than average mass fraction of helium when applying the shielding gases alternately, compare to a premixed gas with the same volume of argon and helium, increased the weld penetration by 13% on average, suggesting a modest improvement in heat transfer

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“…The gas selected will depend on the kind of material to be welded and on the technique used [2]. The kind of gas will determine the bead shape, the stability of the electric arc [3] and the kind of transfer needed [4]. The most commonly used types of transfer for GMAW [5] processes are the short arc [6], [7], spray arc [8] and globular arc [9].…”

Section: Introductionmentioning

confidence: 99%

Experimental Research on the Electrical Parameters of GMAW on Different Positions Welds

Romaní

Meseguer-Valdenebro

Portolés

2016

Trans Indian Inst Met

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This paper presents the influence of the main parameters of the GMAW welding process on ingot iron sized 300 9 125 9 3 mm 3 , with a 1 mm separation between edges and without any bevel preparation. Three gases were used in this research: CO 2 , C15 and C25, with the purpose of studying the shielding influence of each of these gases separately in the welding process. In this research different power ranges were used with the purpose to assure the quality of the surface finish on the bead and the minimum penetration on the plates. The influence of the welding torch's direction of advancement (forehand or backhand) for positions PA, PC and PE were studied together with its influence on the power source. The position which needed the least energy was the PA, followed by position PC and then position PE. The forehand advancement direction required more power than the backhand advancement direction for all positions. The influence of the gases from high to low on the width of the root bead and face bead was C15, CO 2 and C25. This work would be useful to evaluate the influence of the welding parameters on a welding procedure specification with the GMAW welding process. Keywords Welding positions Á GMAW Á Electrical parameters Á Gas Á Forehand Á Backhand List of symbols ASME V American Standard Mechanical Engineers, section V AWS American Welding Society C15 Gas 15 % CO 2 ? 85 % Ar C25 Gas 25 % CO 2 ? 75 % Ar EN European norm GMAW Gas metal arc welding ISO

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Effects of shielding gas compositions on arc plasma and metal transfer in gas metal arc welding

Cited by 42 publications

References 25 publications

Investigation of the effect of torch tilt and external magnetic field on arc during overlapping deposition of wire arc additive manufacturing

Investigation of the effect of torch tilt and external magnetic field on arc during overlapping deposition of wire arc additive manufacturing

Visualisation of alternating shielding gas flow in GTAW

Experimental Research on the Electrical Parameters of GMAW on Different Positions Welds

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