Effect of shielding gas parameters on weld metal thermal properties in gas metal arc welding

Ley, F; Campbell, Stuart; Galloway, Alexander; McPherson, Norman

doi:10.1007/s00170-015-7106-2

Cited by 28 publications

(14 citation statements)

References 25 publications

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“…Lesser linear thermal expansion coefficient, increase in specific heat capacity and thermal conductivity are some of the advantages offered with the application of helium gas. Helium as a shielding gas when delivered at low gas flow rate contributes to a sound part deposition [35].…”

Section: Aero-component (Gasket) Depositionmentioning

confidence: 99%

A bottom-up approach to experimentally investigate the deposition of austenitic stainless steel in laser direct metal deposition system

Pant

Chatterjee

Samanta

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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Direct metal deposition (DMD) is a method of metallic part fabrication under the classification of additive manufacturing process. In DMD, parts are manufactured by melting powder particles reaching the deposition zone, layer by layer with a laser beam. This potential process promises manufacturing flexibility of complex shapes deposition with a range of challenging materials. The work presents the establishment of laser, powder and deposition parameters in a newly developed metal-based direct laser deposition system. The experiments are performed using a 1.2-kW diode laser of 976-nm wavelength coupled with coaxial fed powder delivery nozzle. Geometrical characteristics and mechanical properties of the deposited single-wall, multi-layer wall are determined and discussed. The study also discusses some of the challenges met during the deposition and their potential resolutions. Issues with uniformity of layer width, layer height and mechanical properties such as surface finish and micro-hardness are addressed. The specific aim of this experimental work is to effectively control the process parameters towards building a sound thin wall clad deposition and to further use those parameters for the development of a functional 3D component. A 3D functional component is deposited using 300 W laser power, 4 mm/s scanning speed, 1.05 g/ min powder feed rate and 50% overlap ratio which shows a good geometrical resemblance with the original part. The study thus can provide intuitive guidance for deposition to metal additive manufacturing enthusiasts.

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Section: Aero-component (Gasket) Depositionmentioning

confidence: 99%

A bottom-up approach to experimentally investigate the deposition of austenitic stainless steel in laser direct metal deposition system

Pant

Chatterjee

Samanta

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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“…A lower shielding gas flow rate can result in an increase in temperature [17], which will promote the heat flux being diffused within a shorter space of time. Other studies, including Ley [18], have explored reducing the shielding gas flow rate to improve the thermal conductivity of the weld. A lower shielding gas flow rate showed several beneficial properties such as low thermal expansion, high specific heat capacity, and thermal conductivity.…”

Section: Physical Model Assumptionsmentioning

confidence: 99%

Effects of Welding Speed and Pulse Frequency on Surface Depression in Variable Polarity Gas Tungsten Arc Welding of Aluminum Alloy

Zhao

Wei

2019

Metals

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A three-dimensional (3D) numerical model with the volume of fluid method is developed for high-speed variable polarity gas tungsten arc welding (VP-GTAW) of aluminum alloys. It predicts the thermal flow field in the weld pool, the weld pool surface deformation, and solidified bead geometry during VP-GTAW in successive welding passes. Verification of the numerical model was performed by comparing the calculated results with metallography of welded cross-sections. The prediction showed reasonable accuracy in predicting weld bead geometry. The prediction average relative errors of the bead width and depth of penetration are less than 7%. The deformed weld pool surface, the fluid flow in the weld pool, and maximum fluid temperature in the workpiece based on the developed model, are discussed in detail. The effects of welding speed and pulse frequency on surface depression are studied. The results show that the maximum fluid temperature is closely correlated to the welding speed and pulse frequency. Further, the upper and lower limit of maximum fluid temperature would provide a clue by which the surface depression and the pitch of humps may be recognized. An increase in welding speed will lead to the increase of the pitch of humps, but the reverse is true in the pulse frequency. These detailed physical insights facilitate the prediction of welding surface defects in the high-speed VP-GTAW of aluminum alloy.

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“…A sufficient shielding gas flow rate is necessary to guarantee effective protection; otherwise, the impurities can cause fusion defects and porosity. It is known that a too low flow rate can lead to inadequate coverage of the weld pool [3], while too high flow rate can result in turbulence in the shielding gas column, which promotes the formation of entrapped gas (porosity) during the solidification phase [4]. Another aspect which must be taken into account is the gas waste, since studies show that the cost of shielding gases could reach 25% of the overall welding cost [5].…”

Section: Introductionmentioning

confidence: 99%

A new model to distinguish welds performed by short-circuit GMAW based on FRESH algorithm and MLP ANN

Campos

Amaral

Soares

et al. 2019

J Braz. Soc. Mech. Sci. Eng.

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The short-circuit gas metal arc welding has been continuously studied over the years, due to its important role in manufacturing processes. Concerning the process, many kinds of research are carried out aiming to understand the influence of the shielding gas in welds quality. In this context, this work treats the voltage and current welding signals as time series and applies a feature extraction based on scalable hypothesis tests, which is called FRESH algorithm, in order to obtain the signal features. After that, these features are applied in a multilayer perceptron artificial neural network, trained by the scaled conjugate gradient method, which classifies the welds according to the flow rate and type of shielding gas used in the process. The model presented excellent performance, which shows that the proposal is suitable to be used in welding quality monitoring.

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Effect of shielding gas parameters on weld metal thermal properties in gas metal arc welding

Cited by 28 publications

References 25 publications

A bottom-up approach to experimentally investigate the deposition of austenitic stainless steel in laser direct metal deposition system

A bottom-up approach to experimentally investigate the deposition of austenitic stainless steel in laser direct metal deposition system

Effects of Welding Speed and Pulse Frequency on Surface Depression in Variable Polarity Gas Tungsten Arc Welding of Aluminum Alloy

A new model to distinguish welds performed by short-circuit GMAW based on FRESH algorithm and MLP ANN

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