The arc phenomenon by the characteristic of EN ratio in AC pulse GMAW

Park, Hyoung Jin; Kim, Dong Cheol; Kang, Minjung; Rhee, Sehun

doi:10.1007/s00170-012-4371-1

Cited by 35 publications

(9 citation statements)

References 2 publications

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“…8) in variable polarity aluminum welding up to these days. This 70 % anode heating theory has been widely accepted and applied to VPPA aluminum welding in past research [5,9,13,18]. In these prior arts, a minimal DCEP duty ratio was used to achieve the cleaning effect along with high heat input efficiency, as shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Some of recent gas metal arc welding (GMAW) processes are adopting VP current [12] not like conventional ones which provided DCEP polarity only. Latest research about aluminum VP-GMAW reported deeper penetration for increase DCEP ratio [13], but detailed description for this phenomenon was missed. In the current work, the physics of VP-GTAW has been investigated w.r.t.…”

Section: Introductionmentioning

confidence: 99%

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Heat input analysis of variable polarity arc welding of aluminum

Cho

Lee

Bae

2015

Int J Adv Manuf Technol

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Influence of direct current electrode positive (DCEP) duty ratio in variable polarity (VP) arc welding of aluminum has been investigated in the current work. VP arc adopts alternate current (AC) of DCEP and direct current electrode negative (DCEN) as power source, and the duty ratio indicates the polarity's durational portion in the current pulse. Experimental results showed proportional relationship between heat input and DCEP duty ratio although there was a fluctuation due to the arc instability increase caused by wearing of the tungsten electrode tip. This observation violates the conventional arc theory of anode heating, and therefore, a new theoretical approach combining the tunneling effect and random walk of cathode spot has been proposed. During DCEP duration, arc is concentrated on thinner oxide cathode spot, which further melts and breaks the oxide layer of the spot. This process is repeated at another cathode spot at a high frequency. Therefore, the higher the DECP duty ratio, the more cathode spots are generated and the longer was the arc concentration time. This in turn resulted in a higher heat input for longer DCEP polarity duration. The proposed mechanism combining the tunneling effect and random walk of cathode spot can not only explain the anomalous results of the current research but also could address the ambiguous result of deeper penetration in thicker oxide in the past research.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heat input analysis of variable polarity arc welding of aluminum

Cho

Lee

Bae

2015

Int J Adv Manuf Technol

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“…Park et al [7] investigated the effect of the EN ratio on the wire melting rate, arc melting phenomenon and drop size in the pulsed AC-GMAW process in aluminum welding. They found that, with the increase in EN ratio, the drop sizes and wire melting rate increased, whereas the heat supplied to the BM decreased.…”

Section: Introductionmentioning

confidence: 99%

The Effect of EN Ratio and Current on Microstructural and Mechanical Properties of Weld Joined by AC-GMAW on Square Groove Butt Joints

Ikram¹,

Chung²

2017

Applied Sciences

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Abstract:In the present work, the effect of welding current and electrode negative (EN) ratio on microstructure and mechanical properties of square groove butt joint produced by alternating current gas metal arc welding (AC-GMAW) process has been investigated. The experiments were conducted using different combination of welding current ranging from 150 A to 250 A with three distinct EN ratios i.e., 0%, 30% and 50% on 5 mm thick steel plates at a constant joint gap of 1 mm and welding speed of 10 mm/s. The effect of current and EN ratio on welding soundness was evaluated through optical microscopy, tensile tests and micro-hardness mapping. The results revealed that, at higher values of currents, an increase in EN ratio resulted an increase in penetration depth. It was found that at a current of 250 A and a 50% EN ratio, the deep penetration was obtained.Tensile test results showed that the tensile strength properties improved with increasing current. Furthermore, the micro-hardness distribution was not strikingly affected by changing the EN ratio.

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“…Park et al [13] found that, with the increase in EN ratio, the drop sizes and wire melting rate increased, whereas the heat supplied to the BM decreased. According to Kim and Chung [8], since AC-GMAW exhibits characteristics of both DCEP and DCEN at the same time, it is considered as an effective and productive welding process offering advantages such as low heat input to the base metal, high wire melting rate, and stable arc.…”

Section: Introductionmentioning

confidence: 99%

A contribution to the study of negative polarity in GMA welding

Li¹,

Hurtig

Högström

et al. 2017

Int J Adv Manuf Technol

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Gas metal arc welding (GMAW) using the electrode with negative polarity (DCEN) has been frequently suggested as a potential means of increasing production capacity. The objective of this work was to further study the performance of negative polarity in GMAW of carbon steels. In this project phase, bead-on-plate welds were carried out in flat position to assess the effect of different potential shielding gas compositions on bead geometry, finishing and spattering. The characteristics were compared with DCEP at the same current, but depositing the same volume of material per unit of length (more industrial related comparison). The arc length was kept the same by adjusting voltage to reach shortest arcs, yet with suitable non short-circuiting metal transfer mode. An approach to measure bead convexity was also proposed and assessed. The results showed that DCEN is feasible as a means of increasing GMAW production capacity. However, to become DCEN applicable with GMAW, the results suggest an Ar-based blend with around 6.5% of O 2 is the most appropriate shielding gas, as much as that there is a demand for a standard electronic controlled power source able to work in constant current mode.

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The arc phenomenon by the characteristic of EN ratio in AC pulse GMAW

Cited by 35 publications

References 2 publications

Heat input analysis of variable polarity arc welding of aluminum

Heat input analysis of variable polarity arc welding of aluminum

The Effect of EN Ratio and Current on Microstructural and Mechanical Properties of Weld Joined by AC-GMAW on Square Groove Butt Joints

A contribution to the study of negative polarity in GMA welding

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