A unified model of transport phenomena in gas metal arc welding including electrode, arc plasma and molten pool

Abstract

This paper presents a theoretical model for describing globular transfer in gas metal arc welding. The heat and mass transfer in the electrode, arc plasma and molten pool are considered in one unified model. Using the volume of fluid method, the transport phenomena are dynamically studied in the following processes: droplet formation and detachment, droplet flight in arc plasma, impingement of droplets on the molten pool and solidification after the arc extinguishes. The simulation of heat and mass transfer in the arc plasma considers the developing surface profile of the electrode and molten pool and also the effect of the flying droplet inside the arc plasma. Furthermore, the heat inputs to the electrode and the molten pool result from the simulation of the arc plasma. In addition, a He–Ne laser in conjunction with the shadow-graphing technique is used to observe the metal-transfer process. The theoretical predictions and experimental results are shown to be in good agreement.

Joining of dissimilar materials

“…In gas metal arc welding, higher quality joints and process stability can be achieved by simulation of metal droplet shape and formation in the metal transfer process [73,266]. According to Wang et al [266], methods developed earlier consider effects of surface tension, gravity and electromagnetic force, but heat transfer and phase change effects are not taken into consideration.…”

“…According to Wang et al [266], methods developed earlier consider effects of surface tension, gravity and electromagnetic force, but heat transfer and phase change effects are not taken into consideration. Examples of such methods are: (i) volume of fluid (VOF) and enthalpy methods [56], (ii) one-dimensional analysis [51], (iii) the pinch instability theory, and (iv) static force balance theory [73,266]. Based on these approaches, non-isothermal models were developed, providing an improved description of the metal transfer process [73].…”

“…Examples of such methods are: (i) volume of fluid (VOF) and enthalpy methods [56], (ii) one-dimensional analysis [51], (iii) the pinch instability theory, and (iv) static force balance theory [73,266]. Based on these approaches, non-isothermal models were developed, providing an improved description of the metal transfer process [73]. Wang et al [266] developed a new numerical model based on such approaches as ''the enthalpy, effective-viscosity and VOF methods''.…”

Determination of the momentum of droplets impinging on the pool during aluminium GMAW

“…The authors calculated the kinematic characteristics of the metal transfer, such as droplet acceleration. Yet in the beginning of 2000, Fan and Kovacevic [9] considered in their numeric model for GMAW, the complementary effects of heat transfer and gas flow in the arc and mass transfer from the electrode as a whole, but they also included the effect of droplets reaching the pool. These researchers used experimental data on metallic transfer to refine their models.…”

Methods of mathematical modelling of the processes of electrode metal drop formation and transfer in consumable electrode welding (Review

“…The second group includes the model of drop formation in terms of hydrostatic approximation [9][10][11], as well as models based on equations of motion of viscous incompressible liquid. In its turn, in the subgroup of dynamic models thin jet approximation can be singled out [12][13][14], as well as models based on total system of Navier-Stokes equations [15][16][17][18][19][20]. Let us consider the most widely accepted of the above methods.…”