Three-dimensional turbulent weld pool convection in gas metal arc welding process

Jaidi, Jeevan; Dutta, Pradip

doi:10.1179/136217104225021814

Cited by 17 publications

(15 citation statements)

References 15 publications

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“…For a typical GTA weld pool in low carbon steel with U s = 150 mm/s and r eff = 2.0 mm, d v = 1.0 9 10 À5 m. Evidently, very small elements are in demand within the melt pool necessitating a large number of total elements in the solution domain. However, independent studies with regard to heat transfer and fluid flow analyses in welding [18,20,21] suggest little influence of very fine mesh in the melt pool on the prediction of overall temperature and velocity fields. The minimum element size, therefore, is kept as 3.5 9 10 À5 m in the present work.…”

Section: Computational Aspectsmentioning

confidence: 97%

“…[13][14][15][16] Alternately, the researchers used the k-e based turbulence equation to compute the turbulent kinetic energy and its influence on convective flow in the weld pool, which not only increased computational time and complexity but also added uncertainty in calculations as the k-e based turbulence equation required additional empirical parameters. [17][18][19][20][21] The fact that a certain amount of uncertainty will ever prevail in the computed temperature and velocity fields in the weld pool is, nevertheless, axiomatic. A recourse, therefore, is to develop a relatively simple heat transfer and fluid flow model with a trade-off between the complex thermophysical phenomena in a real weld pool and the extent of the same that can be accounted for with the minimum number of uncertain model input parameters.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Probing Reliability of Transport Phenomena Based Heat Transfer and Fluid Flow Analysis in Autogeneous Fusion Welding Process

Bag

2010

Metall Mater Trans A

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International audienceThe transport phenomena based heat transfer and fluid flow calculations in weld pool require a number of input parameters. Arc efficiency, effective thermal conductivity, and viscosity in weld pool are some of these parameters, values of which are rarely known and difficult to assign a priori based on the scientific principles alone. The present work reports a bi-directional three-dimensional (3-D) heat transfer and fluid flow model, which is integrated with a real number based genetic algorithm. The bi-directional feature of the integrated model allows the identification of the values of a required set of uncertain model input parameters and, next, the design of process parameters to achieve a target weld pool dimension. The computed values are validated with measured results in linear gas-tungsten-arc (GTA) weld samples. Furthermore, a novel methodology to estimate the overall reliability of the computed solutions is also presented

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Section: Computational Aspectsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Probing Reliability of Transport Phenomena Based Heat Transfer and Fluid Flow Analysis in Autogeneous Fusion Welding Process

Bag

2010

Metall Mater Trans A

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“…where q is heat flux (Ref 25), g is the arc efficiency, U w is the welding speed, I is the welding current, r b is the heat distribution parameter, r is the distance between the specific location and the heat source, r is the Stefan-Boltzmann constant, h c is the convective heat transfer coefficient, and T 0 is the ambient temperature. At the y = 0 and symmetric surface:…”

Section: Mathematical Modelmentioning

confidence: 99%

Prediction of Grain Growth Behavior in HAZ During Gas Tungsten Arc Welding of 304 Stainless Steel

Aval

Serajzadeh

Kokabi

2009

J. of Materi Eng and Perform

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In this study, the thermal cycles and the grain structure in the weld heat-affected zone (HAZ) are predicted. At the first stage, a combined heat transfer and fluid flow model is employed to assess the temperature fields during and after welding of 304 stainless steel and then, the evolution of grain structure is conducted using the predicted temperature distribution and an analytical model of grain growth. The grain sizes of the CGHAZ (coarse grain heat affected zone) achieved from the model are basically in agreement with those obtained from experimental measurement under different heat inputs in the range of 0.33-1.07 MJ/m. Both the experimental data and the calculated results show that the average grain size near the fusion plane is about two to four times larger than the average grain size in the base plate depending on the applied heat input.

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“…The second approach, such as the one presented in the present paper, uses analytical models to simulate the heat source and material supply: arc plasma phenomena are not explicitly modelled. Over the years, the simplified Goldak approach and the laminar flow analysis in the weld pool have tended to be replaced by more physically coupled models including a Gaussian surface heat flux and turbulent flows without any enhanced viscosity [9,10,11,12]. However the modelling of turbulent flows has only been proposed in steady conditions, for a coordinate system moving with the heat source.…”

Section: Introductionmentioning

confidence: 99%

“…Unfocused and moderate power laser is used here as an auxiliary heat source, the role of which is essentially to enlarge the welding pool. In addition a third volumetric heat source is implemented to model the heat supply associated with the impingement of molten droplets into the fusion zone [10,14,15,16]. Moreover, for the mass input of these molten droplets, a source term is added to the right hand side of the mass conservation equation for certain liquid finite elements in the fusion zone [25].…”

Section: Introductionmentioning

confidence: 99%

A level set approach for the simulation of the multipass hybrid laser/GMA welding process

Desmaison¹,

Bellet²,

Guillemot³

2014

Computational Materials Science

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A new 3D finite element model, developed in a level set approach, is proposed to model hybrid gas metal arc / laser welding in multipass conditions. This heat and mass transfer model couples the resolution of the heat conservation equation, the momentum and mass conservation equations and the weld bead development. The arc welding total power is divided in two parts: one corresponding to the energy transferred to the fusion zone by droplets of melted filler material, the rest being transferred to the workpiece by the surrounding plasma. The droplets energy input is modelled as a volumetric heat source. Regarding the heat surface fluxes associated with plasma and laser heating, the "Continuum Surface Force" approach is used to model them as volumetric heat sources concentrated in the immediate neighbourhood of the metal-gas interface. A resolution scheme, consisting in ignoring high velocity fluid flow in the fusion zone, through the use of an augmented liquid viscosity, is proposed and discussed. Accordingly, the liquid thermal conductivity is enhanced to result in a realistic heat transfer to the workpiece. The formation of the weld bead is obtained through the introduction of a source term in the mass conservation equation, and the application of the normal component of surface tension forces, proportional to the mean curvature of the metal-gas interface. This approach is proposed to reduce computation time. The resolution scheme is applied to the simulation of hybrid welding of 18MND5 (ASME SA 533) steel grade. Results are compared to experimental measurements and observations operated in conditions close to industrial ones. The influence of the enhancement applied to the liquid conductivity coefficient is shown and discussed. A strong sensitivity evolution is demonstrated when varying it from the physical value to the value proposed in the welding literature. As proposed, the simplified resolution scheme leads to a good estimation of the weld bead surface development. Nevertheless, there are still noticeable differences with the whole set of experimental results that are discussed and can be explained by model limitations and insufficient knowledge of material and interfacial properties.

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Three-dimensional turbulent weld pool convection in gas metal arc welding process

Cited by 17 publications

References 15 publications

Probing Reliability of Transport Phenomena Based Heat Transfer and Fluid Flow Analysis in Autogeneous Fusion Welding Process

Probing Reliability of Transport Phenomena Based Heat Transfer and Fluid Flow Analysis in Autogeneous Fusion Welding Process

Prediction of Grain Growth Behavior in HAZ During Gas Tungsten Arc Welding of 304 Stainless Steel

A level set approach for the simulation of the multipass hybrid laser/GMA welding process

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