Metal vapour behaviour in thermal plasma of gas tungsten arcs during welding

Yamamoto, K.; Tanaka, Manabu; Tashiro, Shinichi; Nakata, Kohei; Yamazaki, Kei; Yamamoto, Eri; Suzuki, Keiichi; Murphy, Anthony B.

doi:10.1179/174329308x319235

Cited by 47 publications

(41 citation statements)

References 21 publications

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“…Figure 6 [9] shows helium arcs on a water-cooled copper plate and on an iron plate. Only helium plasma in a red color can be observed on the water-cooled copper.…”

Section: Temperature Measurement Methodsmentioning

confidence: 99%

“…The mixing phenomenon of the iron vapor with shielding gas was expressed by the diffusion equation [9] as shown in Eq. (3).…”

Section: Numerical Analysis Modelmentioning

confidence: 99%

“…(1), (2), and (3) into the existing two-dimensional GTA model [9]. In addition, it was postulated that the atmospheric gas was the single gas of argon or helium.…”

Section: Numerical Analysis Modelmentioning

confidence: 99%

“…However, it is known that arc plasma having high energy density such as helium arcs or Ar+H 2 mixture arcs generates a large amount of metal vapor from the molten pool [8]. The generated metal vapor affects the heat source characteristics of plasma; and according to the numerical analysis of helium arc by Yamamoto et al [9], for instance, it is reported that the generation of metal vapor lowers the plasma temperature in the vicinity of the molten pool. Hereupon, the relationship between dissociated nitrogen status and plasma temperature is shown in Fig.…”

Section: Nitrogen Content Of Weld Metalmentioning

confidence: 99%

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Effect of plasma heat source characteristics on nitrogen absorption in gas tungsten arc weld metal

et al. 2013

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Effects of plasma heat source characteristics on nitrogen absorption in gas tungsten arc (GTA) weld metal was investigated using two-dimensional spectroscopic measurements and numerical analyses. In the condition of 1 % nitrogen-mixed shielding gas, nitrogen content of weld metal in a helium arc or an argon-hydrogen arc decreased compared to that of an argon arc. These changes in nitrogen content had a strong correlation with arc voltages for the respective shielding gases, so it was considered that nitrogen absorption in weld metal was affected by arc plasma heat source characteristics. The spectroscopic measurements of these arcs showed that the plasma temperature near the molten pool surface in the helium arc or the argon-hydrogen arc indicated around 6,500 K, while the plasma temperature in the argon arc achieved more than 10,000 K. Additionally, from numerical analyses of GTA dealing with metal vapor, it was found that the plasma temperature in the helium arc was reduced by the metal vapor generated from the molten pool. As a result, the reduction of nitrogen disassociation caused by decreasing plasma temperature was considered as the significant factor in lowering nitrogen absorption in the helium arc.

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“…Figure 6 [9] shows helium arcs on a water-cooled copper plate and on an iron plate. Only helium plasma in a red color can be observed on the water-cooled copper.…”

Section: Temperature Measurement Methodsmentioning

confidence: 99%

“…The mixing phenomenon of the iron vapor with shielding gas was expressed by the diffusion equation [9] as shown in Eq. (3).…”

Section: Numerical Analysis Modelmentioning

confidence: 99%

“…(1), (2), and (3) into the existing two-dimensional GTA model [9]. In addition, it was postulated that the atmospheric gas was the single gas of argon or helium.…”

Section: Numerical Analysis Modelmentioning

confidence: 99%

Section: Nitrogen Content Of Weld Metalmentioning

confidence: 99%

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Effect of plasma heat source characteristics on nitrogen absorption in gas tungsten arc weld metal

et al. 2013

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“…And the electrodes properties are given in 4) . The other approximations, governing equations and boundary conditions are given in detail in our previous papers 2,5,6) . …”

Section: Numerical Analysis On Effects Of Power Source Characteristicmentioning

confidence: 99%

Numerical Analysis on Effects of Power Source Characteristics on Arc Properties in Gas Tungsten Arc

Tsujimura

Tashiro

Tanaka

2011

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY

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Arc properties in Gas Tungsten Arc (GTA) strongly depend on welding conditions such as an arc current, an arc length and so on. In GTA, the arc current and an arc voltage are determined by an external characteristic of a power source and an electrical characteristic of the arc. There are two kinds of external characteristics of power sources, namely, Constant Current (CC) and Constant Voltage (CV) characteristics. The electrical characteristic of the arc depends on the arc length. In this study, dependences of the arc properties and relationships between the current and the voltage on the arc length in GTA employing power sources with the CC and the CV characteristics were numerically analyzed. As a result, it was found that the voltage and power of the arc decreased with decrease of the arc length in case of the CC characteristic and the current and the power of the arc increase dramatically with decrease of the arc length in case of the CV characteristic. Furthermore, with variation of the arc length, the arc power hardly changes for the CC characteristic, although the arc power largely changes for the CV characteristic.

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Modeling of Thermal Plasma Processes: The Importance of Two‐Way Plasma‐Surface Interactions

Murphy

Park

2016

Plasma Processes & Polymers

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Most thermal plasma applications involve interactions between the plasma and solid or liquid surfaces. Computational models of thermal plasma applications typically consider the influence of the plasma on the surface, but often neglect the effect of the surface on the plasma. In many cases, however, it is not possible to accurately model the plasma process without taking the two‐way interactions into account. This is demonstrated using examples from arc welding, plasma cutting, plasma‐particle interactions, such as occur in plasma spheroidization, plasma nanoparticle production and plasma spraying, and high‐ and low‐voltage circuit breakers. Vaporization of metal, ceramic and polymer surfaces, transfer of heat and momentum from the plasma to particles and droplets, and changes in the surface shape are all shown to affect the properties of the plasma.

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Metal vapour behaviour in thermal plasma of gas tungsten arcs during welding

Cited by 47 publications

References 21 publications

Effect of plasma heat source characteristics on nitrogen absorption in gas tungsten arc weld metal

Effect of plasma heat source characteristics on nitrogen absorption in gas tungsten arc weld metal

Numerical Analysis on Effects of Power Source Characteristics on Arc Properties in Gas Tungsten Arc

Modeling of Thermal Plasma Processes: The Importance of Two‐Way Plasma‐Surface Interactions

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