Research On Arc-swing Narrow Gap MIG Of Thick-wall Aluminium Alloy

As the progress of industrial, the application of aluminum alloy plate is more andmore widespread. Narrow gap welding technology is a highly efficient weldingtechnology, when welding thick plate can effectively increase productivity and reducedeformation. But the disadvantage is prone to sidewall infusion, using swing-arc canincrease heat input and improve it. In this paper, design a new welding torch for narrowgap MIG welding with swing-arc， analyze droplet transfer characteristics andtemperature distribution, explanation the impact of the swing-arc on welding processand research the influence of different parameters on welding process, get the optimalparameter interval and obtain a good quality welded joint.This article has designed a narrow gap MIG welding torch with swing-arc, aneccentric tip has been used, when the motor driven gear rotating, the wire tip followeddo cyclical swing. Design a double gas nozzle, the inside one can insert into the grooveand can slide on the outside one,which have a deep significance for welding deepgroove，the torch structure is compact, have a good property.Using high-speed camera and current-voltage signal acquisition system analyzedroplet transfer characteristics. Comparing with and without wire swing discover swingarc can promote droplet transition. In narrow gap welding process, globular transferappears when the wire moves to the middle of the groove, and the projected transferhappened at the side wall. From the collected signal can be seen current increases whenthe wire close to the side wall, current reaches a minimum when the wire at middlegroove. When the welding parameters change, droplet forms comply with the aboveconclusions, but the frequency and droplet diameter will change, thus affecting theshape of the pool, which is closely related with the final weld shape.The swing welding temperature field model has been established to study thedistribution of temperature field, and to explain the swing arc’s function from theperspective of energy. By analysis the influence of welding parameters on thetemperature field distribution to explain its impact on weld forming.The20mm width2219aluminum alloy has been welded for single-pass andsingle-layer Process. Through study the influence of wire feed speed, welding speed, thesidewall residence time, swing width on the welding process to get the optimalparameter interval and to obtain a good quality welded joint with multilayer for40mm.