On the calculation of the free surface temperature of gas-tungsten-arc weld pools from first principles: Part II. modeling the weld pool and comparison with experiments

This paper details three phases of testing to confirm use of a Gas Tungsten Arc (GTA) system for closure welding the 3013 outer container used for stabilization/storage of plutonium metals and oxides. The outer container/lid closure joint was originally designed for laser welding, but for this application, the gas tungsten arc (GTA) welding process has been adapted. The testing progressed in three phases: (1) system checkout to evaluate system components for operational readiness, (2) troubleshooting to evaluate high weld failure rates and develop corrective techniques, and (3) pre-installation acceptance testing. A total of 190 can/lid welds were made and evaluated. During Phase I, weld failures were common due to pressure buildup and venting through the weld pool. During Phase II, characterization of the electrode contact to the weld pool and weld pool blowouts helped in the development of a corrective technique. During Phase III, a reduction in internal pressure, by controlling the final helium backfill of the can before welding, provided satisfactory weld results. The work described was performed during 2002 pre-installation testing at the Savannah River Technology Center in Aiken, S.C. before installation of an Outer Can Welder (OCW) system at the Savannah River Site (SRS) plutonium processing facility. The first OCW system was originally developed at the SRS to support similar plutonium stabilization/storage efforts at the Hanford Site (operated by Fluor Hanford Corporation).

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Numerical analysis of internal flow of molten pool in pulsed gas tungsten arc welding using a fully coupled model with free surface

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2020.120572 ◽

2021 ◽

Vol 165 ◽

pp. 120572

Author(s):

Daqing Wang ◽

Hao Lu

Keyword(s):

Free Surface ◽

Numerical Analysis ◽

Arc Welding ◽

Molten Pool ◽

Coupled Model ◽

Internal Flow ◽

Gas Tungsten Arc Welding ◽

Gas Tungsten Arc ◽

Gas Tungsten ◽

Fully Coupled

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Numerical Analysis of Fully Penetrated Weld Pools in Gas Tungsten Arc Welding

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/pime_proc_1996_210_185_02 ◽

1996 ◽

Vol 210 (2) ◽

pp. 187-195 ◽

Cited By ~ 21

Author(s):

Y M Zhang ◽

Z N Cao ◽

R Kovacevic

Keyword(s):

Free Surface ◽

Weld Pool ◽

Driving Forces ◽

Numerical Models ◽

Surface Tension Gradient ◽

Bottom Surface ◽

Welding Parameters ◽

Back Side ◽

Full Penetration ◽

Weld Pools

Full penetration welding is widely used in metal joining, but it has been ignored in previous convective numerical models. In addition to the free surface on top of the pool, an additional free surface appears on the bottom of the workpiece. It can be shown that the top surface, temperature distribution and fluid flow field in the weld pool are all coupled with the pool's bottom surface. This complicates the numerical process and therefore no convective models have previously been developed for fully penetrated weld pools. In order to improve the numerical solution for the fully penetrated weld pool, a three-dimensional model is proposed. Free top and bottom pool surfaces have been included. The electromagnetic force, buoyancy force and surface tension gradient (Marangoni) are the three driving forces for weld pool convection. Welding parameters are changed in order to analyse their effects on weld pool geometry. It is found that the depression of the top surface contains abundant information about the full penetration state as specified by the back-side bead width.

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