Modelling the keyhole double-sided arc welding process

Double-sided arc welding is a novel arc process in which the workpiece is disconnected from the power supply and the two torches are used to establish two arcs oil the both sides of the workpiece to close the current loop. As a result, the welding current is forced to flow through the workpiece along the thickness direction. This configuration and current flow direction improve the concentration of the are energy distribution and provide a mechanism to guide the arc into into keyhole. Hence, double-sided arc welding is capable of achieving deep, narrow penetration and symmetrical welds. However, despite the progress in process development, there is a lack of a clear understanding of the physical processes and phenomena occurring in the weldment. In this study, a numerical model is developed to compute the temperature field and history in double-sided arc weldment. Using this numerical model, the temperature distributions and profiles at. different cross sections and along different lines of interest have been computed and compared with the results in regular plasma arc welding. It was found that the double-sided arc welding process has a dvanta-es ill obtaining deep, narrow Penetration, ill producing symmetrical hour glass-shape d welds, in reducing the sensitisaton zone, in lowering the temperature gradient along the thickness, thus lowering the thermal distortiori and residual stress, and ill decreasing the sensitisation duration.