Numerical simulation of fluid flow and temperature field in keyhole double‐sided arc welding process on stainless steel

Abstract

SUMMARYDouble-sided arc welding process powered by a single supply is a type of novel high-production process. In comparison with the conventional single-sided arc welding, this process has remarkable advantages in enhancing penetration, minimizing distortion and improving welding production. In this paper, a three-dimensional steady numerical model is developed for the heat transfer and fluid flow in plasma arc (PA)-gas tungsten arc (GTA) double-sided keyhole welding process. The model considers the surface tension gradient, electromagnetic force and buoyancy force. A CCD camera is used to observe the size and shape of the keyhole and weld pool. The acquired images are analysed through image processing to obtain the surface diameters of the keyhole on the two sides. A double-V-shaped keyhole geometry is then proposed and its characteristic parameters are derived from the images and cross-section of weld bead. In the numerical model, the keyhole cavum within the weld pool is treated as a whole quality, whose temperature is fixed at the boiling point of the workpiece material. The heat exchange between the keyhole and weld pool is treated as an interior boundary of the workpiece. Based on the numerical model, the distributions of the fluid flow and temperature field are calculated. A comparison of cross-section of the weld bead with the experimental result shows that the numerical model's accuracy is reasonable.

Electromagnetic–Computational Fluid Dynamics Couplings in Tungsten Inert Gas Welding Processes—Development of a New Linearization Procedure for the Joule Production Term

“…Lundbäck et al [6] performed computations and experiments with two plates but without any filler material between them and demonstrated the sensitivity of the model with buckling. Honggang et al [7] developed a 3D model of a double-sided welding process using a plasma torch on one side and a gas tungsten arc (GTA) torch on the other side. Zhan et al [8] developed a 3D model of a laser-metal inert gas (MIG) hybrid welding process, with an approach based on different types of heat sources and without any consideration of the arc.…”

“…2µ e v r 2 + F r (7) where µ e stands for the effective dynamic viscosity, u and v are the axial and radial components of the velocity, and p is the static pressure. The realizable k-ε turbulence model was selected to consider turbulence effects through the turbulent viscosity so that µ e = µ t + µ.…”

Analytical thermal model of conduction mode double sided arc welding

“…There have also been a number of attempts recently to develop more sophisticated numerical thermofluids models of this keyhole mode DSAW process. [24][25][26] However, no models have as yet been derived for the conduction mode DSAW process. 19,20 Hong et al 27 have shown that the effects of fluid flow on weld pool dimensions and shape in fusion welds are negligible for high thermal conductivity metals such as Al and Cu alloys.…”