Influence of shielding gas composition on molten metal flow behavior during plasma keyhole arc welding process

Nguyen, Anh V.; Tashiro, Shinichi; Ngo, Manh Huu; Le, Anh H.; Bui, Hanh Van; Tanaka, Manabu

doi:10.1016/j.jmapro.2020.03.031

Cited by 23 publications

(13 citation statements)

References 18 publications

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“…It is suggested that this keyhole shape strongly depends on the torch design and operating parameters as described above. Nguyen et al studied the effects of plasma gas flow rate [ 67 ], current [ 68 ], and oxygen concentration in shielding gas [ 69 ] in KPAW of a steel plate. In addition, Xu et al clarified the effects of electrode setback [ 70 ] and plate thickness [ 71 ] in VPPAW of aluminum alloys.…”

Section: Keyhole Formation Processmentioning

confidence: 99%

“…Figure 6 shows the effect of oxygen concentration in the shielding gas on the keyhole shape [ 69 ]. Here, a small amount of oxygen is mixed in the shielding gas, assuming shielding failure.…”

Section: Keyhole Formation Processmentioning

confidence: 99%

“…It also causes a variation in the heat transport in the weld pool. Nguyen et al studied the effect of plasma gas flow rate [ 67 ], welding current [ 68 ], and also the shielding gas composition [ 69 ], and Xu et al clarified the effects of electrode setback [ 70 ] and plate thickness [ 71 ] in VPPAW of aluminum alloys. Those studies used the same comprehensive experimental approach.…”

Section: Weld Pool Formation Processmentioning

confidence: 99%

“…Figure 16 shows 3D convective patterns inside the weld pool for different shielding gas compositions [ 69 ]. The weld bead appearances and cross sections of the weld beads have already been presented in Figure 6 .…”

Section: Weld Pool Formation Processmentioning

confidence: 99%

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Interaction Mechanism of Arc, Keyhole, and Weld Pool in Keyhole Plasma Arc Welding: A Review

Tashiro

2024

Materials

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The Keyhole Plasma Arc Welding (KPAW) process utilizes arc plasma highly constricted by a water-cooled cupper nozzle to produce great arc pressure for opening a keyhole in the weld pool, achieving full penetration to the thick plate. However, advanced control of welding is known to still be difficult due to the complexity of the process mechanism, in which thermal and dynamic interactions among the arc, keyhole, and weld pool are critically important. In KPAW, two large eddies are generally formed in the weld pool behind the keyhole by plasma shear force as the dominant driving force. These govern the heat transport process in the weld pool and have a strong influence on the weld pool formation process. The weld pool flow velocity is much faster than those of other welding processes such as Tungsten Inert Gas (TIG) welding and Gas Metal Arc (GMA) welding, enhancing the heat transport to lower the weld pool surface temperature. Since the strength and direction of this shear force strongly depend on the keyhole shape, it is possible to control the weld pool formation process by changing the keyhole shape by adjusting the torch design and operating parameters. If the lower eddy is relatively stronger, the heat transport to the bottom side increases and the penetration increases. However, burn-through is more likely to occur, and heat transport to the top side decreases, causing undercut. In order to realize further sophistication of KPAW, a deep theoretical understanding of the process mechanism is essential. In this article, the recent progress in studies regarding the interaction mechanism of arc, keyhole, and weld pool in KPAW is reviewed.

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Section: Keyhole Formation Processmentioning

confidence: 99%

Section: Keyhole Formation Processmentioning

confidence: 99%

Section: Weld Pool Formation Processmentioning

confidence: 99%

Section: Weld Pool Formation Processmentioning

confidence: 99%

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Interaction Mechanism of Arc, Keyhole, and Weld Pool in Keyhole Plasma Arc Welding: A Review

Tashiro

2024

Materials

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“…In recent years, most researchers have focused on establishing the analytic/numerical models based on integration of plasma arc-molten pool-keyhole characteristics to investigate the mechanism of the keyhole pool behavior and weld formation [3], [4]. The accuracy and reliability of analytic/numerical models may be sensitive to the plenty of factors and assumptions due to the extremely complicated plasma arc welding (PAW) process.…”

Section: B Related Workmentioning

confidence: 99%

Visual-Acoustic Penetration Recognition in Variable Polarity Plasma Arc Welding Process Using Hybrid Deep Learning Approach

Huang

Zhang

et al. 2020

IEEE Access

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Accurate characterization of keyhole pool behavior is important to improve the penetration recognition and quality detection during the variable polarity plasma arc welding (VPPAW) of aluminum alloy. However, the low-level hand-crafted visual/acoustic features are often incapable of sufficiently representing the dynamic characteristics of keyhole pool under complex welding conditions. In this paper, we developed an end-to-end visual-acoustic penetration recognition (VAPR) framework based on a hybrid convolutional neural network (CNN) and extreme learning machine (ELM), which consists of three consecutive phases: (1) visual-acoustic data preparation, (2) multi-features extraction, and (3) penetration classification. Specifically, we applied a flexible dual-sensor acquisition system for synchronously collecting/preprocessing the visual-acoustic signals and exploring the internal correlation between the visual-acoustic features and keyhole pool behavior as well as weld penetration status. Then we established two individual CNNs for learning high-level visual-acoustic features directly from the raw visual images and 2-D time-frequency spectrograms. With the visualization of CNN-based deep learning features, we also explained the physical meanings of visual-acoustic features. To further improve the prediction performance of CNN model, we employed the ELM model as a strong tool to classify penetration status. By comparing with other state-of-the-art methods, our hybrid CNN-ELM approach with visual-acoustic fusion has a superior performance in terms of the classifying accuracy. The VAPR framework in this paper will provide some guidance for post-process quality inspection and realize an adaptive control of VPPAW process.

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Elucidate Fluid Vortex in Plasma Arc Welding

Nguyen

Van

Tashiro

et al. 2021

Lecture Notes in Mechanical Engineering

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Influence of shielding gas composition on molten metal flow behavior during plasma keyhole arc welding process

Cited by 23 publications

References 18 publications

Interaction Mechanism of Arc, Keyhole, and Weld Pool in Keyhole Plasma Arc Welding: A Review

Interaction Mechanism of Arc, Keyhole, and Weld Pool in Keyhole Plasma Arc Welding: A Review

Visual-Acoustic Penetration Recognition in Variable Polarity Plasma Arc Welding Process Using Hybrid Deep Learning Approach

Elucidate Fluid Vortex in Plasma Arc Welding

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