Simulations of weld pool dynamics in V-groove GTA and GMA welding

Cho, Dae-Won; Na, Suck-Joo; Cho, Min-Hyun; Lee, Jong-Sub

doi:10.1007/s40194-012-0017-z

Cited by 50 publications

(23 citation statements)

References 6 publications

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“…The temperature-dependent properties were used for the density. The electromagnetic force, as an important body force, was considered by adopting the elliptically symmetric welding current density [25,26]. The equations relating to the EMF are listed as below.…”

Section: Body Forcementioning

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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Section: Body Forcementioning

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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“…The temperature-dependent properties were used for the density. The electromagnetic force, as an important body force, was considered by adopting the elliptically symmetric welding current density [29,30]. The equations relating EMF are listed as below.…”

Section: ð22þmentioning

confidence: 99%

Heat and Mass Transfer of Additive Manufacturing Processes for Metals

Wei¹,

Du²

2019

Heat and Mass Transfer - Advances in Science and Technology Applications

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Additive manufacturing (AM), a method in which a part is fabricated layer by layer from a digital design package, provides the potential to produce complex components at reduced cost and time. Many techniques (using many different names) have been developed to accomplish this via melting or solid-state joining. However, to date, only a handful can be used to produce metallic parts that fulfill the requirements of industrial applications. The thermal physics and weld pool behaviors in metal AM process have decisive influence on the deposition quality, the microstructure and service performance of the depositions. Accurate analysis and calculation of thermal processes and weld pool behaviors are of great significance to the metallurgy analysis, stress and deformation analysis, process control and process optimization etc. Numerical modeling is also a necessary way to turn welding from qualitative description and experience-based art into quantitative analysis-and science-based engineering branch. In this chapter, two techniques for producing metal parts are explored, with a focus on the thermal science of metal AM: fluid flow and heat transfer. Selective laser melting (SLM) is the one that is most widely used because it typically has the best resolution. Another is named metal fused-coated additive manufacturing (MFCAM) that is cost competitive and efficient in producing large and middle-complex components in aerospace applications.

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“…2 and the experiment conditions for the 2nd pass GMAW, as written in Table 1. The mesh density used in the simulation was 0.25 mm/mesh to determine the molten pool behaviors because previous studies used at least four meshes for the droplet diameter [12,[14][15][16]. All the simulations were conducted by transient numerical analysis.…”

Section: Materials Shape and Mesh Sizementioning

confidence: 99%

“…if y < arc center of y-direction Previous studies [7,15,16] used a total arc heat efficiency of 0.8 which includes the heat transfer by the droplet and arc. The heat efficiency [15] of the droplet and arc can be calculated from Eqs.…”

Section: Arc Heat Source Modelmentioning

confidence: 99%