Molten pool behaviors and forming appearance of robotic GMAW on complex surface with various welding positions

The Effect of Groove Shape on Molten Metal Flow Behaviour in Gas Metal Arc Welding

“…The frequency of droplet detachment is directly proportional to the wire feed rate and ranges between 147 Hz and 187 Hz for the welding process parameters studied in the present work (see Table 1 ). To simplify the numerical simulations and as described in Section 3.1 , the filler metal droplets are assumed to be spherical and are incorporated into the simulations with predefined velocity and temperature, which is a common practice in modelling melt-pool behaviour in gas metal arc welding (see, for instance, [ 7 , 8 , 18 , 21 ]). The qualitative melt-pool behaviour was found to be similar for different welding currents studied in the present work.…”

“…Employing a temperature-dependent density model, thermal buoyancy forces are accounted for in the simulations. In the present work, the properties of the shielding gas are assumed to be temperature-independent, which is a common assumption in numerical simulations of arc welding and additive manufacturing where the melt-pool is decoupled from the arc plasma [ 7 , 8 , 9 , 11 , 12 , 13 , 22 ]. This assumption is justifiable as the transport properties of the shielding gas (i.e., viscosity, density and thermal conductivity) are small compared to those of the molten metal, and thus changes in the shielding gas properties with temperature negligibly affect the numerical predictions of fluid flow in the melt pool [ 24 ].…”

“…To date, focus has predominantly been placed on developing numerical simulations to describe melt-pool behaviour in arc welding of flat plates without a groove (i.e., bead-on-plate welding, see for instance, [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]); however little attention has been paid to understanding the effect of joint shape on complex heat and molten metal flow. Zhang et al [ 16 , 17 ] developed a three-dimensional model in a body-fitted coordinate system to describe the effects of various driving forces on heat and fluid flow in the melt pool during GMAW fillet welding.…”

The Effect of Groove Shape on Molten Metal Flow Behaviour in Gas Metal Arc Welding

“…The frequency of droplet detachment is directly proportional to the wire feed rate and ranges between 147 Hz and 187 Hz for the welding process parameters studied in the present work (see table 1). To simplify the numerical simulations and as described in section 3.1, the filler metal droplets are assumed to be spherical and are incorporated into the simulations with predefined velocity and temperature, which is a common practice in modelling melt-pool behaviour in gas metal arc welding (see for instance, [7,8,18,21]).…”

Effect of Substrate Orientation on Melt Pool during Multi-Layer Deposition in V-Groove with Gas Metal Arc

“…However, the freedom for tilting the arc axis to maintain it normal to a non-horizontal substrate can be limited by defect formation such as overflow, undercut and hump. The effect of the welding position on the molten pool behaviour and resulting bead geometry was studied both experimentally (e.g., Park et al [1]) and numerically (e.g., Hu et al [2], Cho et al [3]) with GMA processing, single bead deposit, and flat, overhead, and vertical welding position. These authors observed that while the flat position generated continuous bead without noticeable defects, the overhead and vertical up positions were prompt to hump formation.…”