Plasma arc welding of pipelines: A study to optimise welding conditions for horizontal fixed joints of mild steel pipes

Narita, Kunio; Takagi, Kenji; Kimura, Takehiro; Mitsui, Akio

doi:10.1016/0308-0161(75)90009-5

Cited by 8 publications

(4 citation statements)

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“…Metcalfe et al [11], for instance, measured the efflux plasma from the backside of the keyhole to indicate the moment of open keyhole establishment. Other studies, like that of Zhang et al [12], attempted to detect the keyhole states using a plasma cloud sensor from above the top surface of the keyhole.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on the weld pool formation process in plasma keyhole arc welding

Van

Tashiro

Hanh

et al. 2017

J. Phys. D: Appl. Phys.

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This paper seeks to clarify the weld pool formation process in plasma keyhole arc welding (PKAW). We adopted, for the first time, the measurement of the 3D convection inside the weld pool in PKAW by stereo synchronous imaging of tungsten tracer particles using two sets of x-ray transmission systems. The 2D convection on the weld pool surface was also measured using zirconia tracer particles. Through these measurements, the convection in a wide range of weld pools from the vicinity of the keyhole to the rear region was successfully visualized. In order to discuss the heat transport process in a weld pool, the 2D temperature distribution on the weld pool surface was also measured by two-color pyrometry. The results of the comprehensive experimental measurement indicate that the shear force due to plasma flow is found to be the dominant driving force in the weld pool formation process in PKAW. Thus, heat transport in a weld pool is considered to be governed by two large convective patterns near the keyhole: (1) eddy pairs on the surface (perpendicular to the torch axis), and (2) eddy pairs on the bulk of the weld pool (on the plane of the torch). They are formed with an equal velocity of approximately 0.35 m s−1 and are mainly driven by shear force. Furthermore, the flow velocity of the weld pool convection becomes considerably higher than that of other welding processes, such as TIG welding and GMA welding, due to larger plasma flow velocity.

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Section: Introductionmentioning

confidence: 99%

Experimental investigation on the weld pool formation process in plasma keyhole arc welding

Van

Tashiro

Hanh

et al. 2017

J. Phys. D: Appl. Phys.

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“…This leads to increase the current density, the heat flux and arc pressure under the thermal pinch effect [4]. Because PKAW has better advances over conventional TIG welding and GMA welding in welding mid-thickness plates [5], and laser beam welding and electron beam welding in equipment cost, safety condition, and operation convenience [6], it has been utilized to join the structures of aerospace [7], automobile [8], rocket [9] and structural steel [10], aluminium [11,12], etc.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Eddy Formation and Heat Transfer Process in Weld Pool during Plasma Keyhole Arc Welding

Anh¹,

Manhh²,

Mai³

et al. 2020

Preprint

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This investigation aims to discuss the formation process of eddies and the heat transportation in plasma keyhole arc welding. In order to clarify this issue, the measurement of the convection inside the weld pool, the convection on the weld pool surface, also the temperature distribution on the weld pool surface were carried out. The results showed that two eddies were found in the weld pool, which is controlled mainly through the shear force by the plasma flow acting on the weld pool surface. The magnitude, extent and direction of the shear force are thought to be determined primarily by the variation of keyhole profile. The relative shape and strength of each eddy is largely changed depending on the change of the keyhole profile when nozzle diameter changed. These relative strengths of each eddy are considered to decisively govern the heat transport in the weld pool coinciding with the direction of eddies. A larger eddy near the lower part of the keyhole inside the weld pool was found out in the case of 1.6 mm, meanwhile a upward larger eddy was found out near the upper part of the keyhole inside the weld pool in the case of 2.4 mm.

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“…A two-dimensional (2D) parameter envelope method has been utilised for selecting appropriate welding parameters. 1–5 The dominant weld pool responses which are generally observed in keyhole welding are partial penetration, full penetration and cutting . Extensive experimental work was carried out on 2.1 mm thick Ti–6Al–4V plates in order to identify 2D parametric envelopes between current and traverse speed for four different plasma gas flow rates (PGFRs).…”

Section: Introductionmentioning

confidence: 99%

Finite element-based analysis of experimentally identified parametric envelopes for stable keyhole plasma arc welding of a titanium alloy

Deshpande

Short²,

Sun

et al. 2012

The Journal of Strain Analysis for Engineering Design

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Finite element modelling of the experimentally obtained parametric envelopes for stable keyhole plasma arc welding was performed using a three-dimensional conical Gaussian heat source. Uncoupled steady-state and transient heat transfer analyses were performed to predict fusion zones and thermal histories. The heat source definition was validated against the experimentally obtained macrograph and thermal history for a representative stable keyhole condition. The paper investigates the relationships between the primary welding parameters, i.e. current, traverse speed, plasma gas flow rate and the weld efficiency, using inverse finite element modelling. The effect of the change of plasma gas flow rate on weld efficiency was estimated by iteratively changing the efficiency to match the experimental results. The numerical–experimental approach is proposed to establish relationships between welding parameters and weld efficiency which can be utilised to understand the underlying physics of keyhole plasma arc welding. The inversely identified relationships between key welding parameters can be useful in selecting the appropriate combination of weld parameters for stable keyhole welding.

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Plasma arc welding of pipelines: A study to optimise welding conditions for horizontal fixed joints of mild steel pipes

Cited by 8 publications

References 0 publications

Experimental investigation on the weld pool formation process in plasma keyhole arc welding

Experimental investigation on the weld pool formation process in plasma keyhole arc welding

Analysis of Eddy Formation and Heat Transfer Process in Weld Pool during Plasma Keyhole Arc Welding

Finite element-based analysis of experimentally identified parametric envelopes for stable keyhole plasma arc welding of a titanium alloy

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