Comparing CW-GMAW in direct current electrode positive (DCEP) and direct current electrode negative (DCEN)

Assunção, P. D. C.; Ribeiro, Rodrigo Alves; Santos, E. B. F.; Braga, Eduardo de Magalhães; Gerlich, A.P.

doi:10.1007/s00170-019-04175-2

Cited by 11 publications

(2 citation statements)

References 14 publications

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“…There are several alternatives for raising the efficiency of GMAW process, such as using direct current electrode negative (DCEN) operation, extended electrical stick out, high operating current, or a combination of these effects [ 5 , 6 , 7 , 8 ]. Operating GMAW with DCEN can increase the burn off rate of the wire by up to 50%, but the electric arc behaves erratically [ 9 ]. The extension of electrical stick out will enhance the deposition rate due to the increased resistive heating of the wire, but this may affect the protection effect of the shielding gas [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Integrated Circular Triple-Wire Pulse GMAW of Q960E High-Strength Steel for Construction Machinery

Wang

Duan³

et al. 2021

Materials

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Multi-wire welding has received much attention in the machinery industry due to its high efficiency. The aim of this study was to investigate a novel pulse gas metal arc welding (GMAW) that has circular triple-wire electrodes. The effect of the pulse phage angle on arc stability was particularly studied. Research showed that for typical phase angles the arc stability from low to high is 180°, 0°, and 120°, and the arcs are very stable at 120°. The triple-wire welding was used to weld a 9 mm thick Q960E steel, which is typically used for the arm of construction machinery. When the welding heat input was controlled at 1.26–1.56 kJ/mm, the weld zone was dominated by acicular ferrite, and the coarse-grained zone of the heat-affected zone was a mixed structure of lath martensite and lath bainite. The tensile strength of the welded joint reached 85% of the base metal and the impact toughness was above 62 J, which can meet the requirements of construction machinery. This indicates that the triple-wire welding has great potential to achieve efficient and high-quality welding for the construction machinery.

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Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Integrated Circular Triple-Wire Pulse GMAW of Q960E High-Strength Steel for Construction Machinery

Wang

Duan³

et al. 2021

Materials

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“…It should be noticed that because of the location where the WFS is measured (before the main drive roller assembly) the advance and retreat movements performed by the secondary drive roller (in the torch) are not perceived in the results, as such movements are accommodated in the buffer of the CMT process. As the fusion capacity in GMA processes is higher when in the negative polarity time, as in this case the arc climbs the electrode-wire in the search for oxides for Figure 4 Number of short-circuits in each semi-cycle (EP and EN) and total number of short-circuits in a full cycle for the entire spectrum of the EP/EN parameter cathodic emission (Li et al, 2018;Assunção et al, 2019;Souza et al, 2010) and boosts its heating, the CMT advanced process compensates that by making the current contribution (directly proportional to its intensity) to the melting rate as being relatively smaller during the EN semi-cycles than it is in the EP semi-cycles, as seen in Figure 5. Therefore, it was found that, despite the current levels being lower during the EN semicycles, the melting rate of the wire remains the same all the way through and the WFS level can be kept constant.…”

Section: Cold Metal Transfer Advanced Process Working Featuresmentioning

confidence: 99%

Effect of the CMT advanced process combined with an active cooling technique on macro and microstructural aspects of aluminum WAAM

Teixeira

Scotti

Reis

et al. 2021

RPJ

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Purpose This paper aims to assess the combined effect of the Cold Metal Transfer (CMT) advanced process and of a thermal management technique (near immersion active cooling [NIAC]) on the macro and microstructure of Al wall-like preforms built by wire arc additive manufacturing (WAAM). As specific objective, it sought to provide information on the effects of the electrode-positive/electrode-negative (EP/EN) parameter in the CMT advanced process fundamental characteristics. Design/methodology/approach Initially, bead-on-plate deposits were produced with different EP/EN ratios, still keeping the same deposition rate, and the outcomes on the electrical signal traces and bead formation were analyzed. In a second stage, the EP/EN parameter and the layer edge to water distance (LEWD) parameter from the NIAC technique were systematically varied and the resultant macro and microstructures compared with those formed by applying natural cooling. Findings Constraints of EP/EN setting range were uncovered and discussed. The use of the NIAC technique favors the formation of finer grains. For a given EP/EN value, a variation in the NIAC intensity (LEWD value) showed marginal effect on grain size. When the EP/EN parameter effect is isolated, i.e. for a given LEWD setting, it was observed that an increase in the EP/EN level favors coarser grains. Originality/value Both the EP/EN parameter and the use of an active cooling technique (NIAC) might be used, even in combination, as effective tools for achieving proper macro and microstructure in WAAM of thin wall builds.

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The effect of pulsed cold-wire feeding on the performance of spray GMAW

Jorge

Scotti

Reis

et al. 2020

Int J Adv Manuf Technol

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Comparing CW-GMAW in direct current electrode positive (DCEP) and direct current electrode negative (DCEN)

Cited by 11 publications

References 14 publications

Experimental Investigation of Integrated Circular Triple-Wire Pulse GMAW of Q960E High-Strength Steel for Construction Machinery

Experimental Investigation of Integrated Circular Triple-Wire Pulse GMAW of Q960E High-Strength Steel for Construction Machinery

Effect of the CMT advanced process combined with an active cooling technique on macro and microstructural aspects of aluminum WAAM

The effect of pulsed cold-wire feeding on the performance of spray GMAW

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