The Research On Metal Transfer Heat Input And The Distribution Of Residual Stress Of Double Electrode GMAW

Dual-electrode Gas Metal Arc Welding has many forms: DE-GMAW, pulse DE-GMAW, double wire DE-GMAW,The rule of the transition which was affected by thewelding parameters on fusion drops, heat distribution rule between work-piece andinput and welding residual stress field distribution were studied through seriousexperiment and theoretical analysis.Fist，Aiming at the dual bypass MIG welding process, this paper took pictures of theprocess of metal transfer under different bypass currents using the high speed cameraand obtained the data of metal transfer by the image processing. The main forcesaffected the drop was calculated by the data. In addition, this paper also compared thesituation of force under different welding parameters which act on the drop andresearched the mechanism of metal transfer promoted. The results indicated thatelectromagnetic force has the most important influence to the process of metal transferof the dual bypass MIG welding. By the promoting of expand the area of arc root, thebypass arcs promote the metal transfer of the dual bypass MIG welding and thisinfluence will be increased by bypass current. Moreover, with the increase of bypasscurrent, the frequency of the metal transfer could be increased and the size of the dropwas decreased when the total current was constant. The type of metal transfer waschanged to spray transfer from globular transfer.secondly, in order to study welding heat distribution rule through welding parameters,the MIG welding arc welding bypass coupling in the process of thermal cycling curvewas measured and analyzed. Analysis indicates that the total current is unchangeable,along with the increase of the current bypass; heat input in work-piece is much less.finally, in order to study the Dual-electrode Gas Metal Welding welding residual stressdistribution rule which was influenced by welding parameters, the welding dimensionand residual stress of different bypass welding parameters were measured. Also theywere compacted by CMT results.Finally, the overlay welding by double wire DE-GMAW and traditional MIG welding were conduct, and the welding thermal cycles were measured in the conditionof the welding process with different welding parameters. And the character of thewelding thermal cycles and the microstructure in the HAZ under different weldingparameters were analyzed and compared with the traditional MIG welding. Resultsshowed that double wire DE-GMAW had low base-metal heat-input and high thermalefficiency had high deposition rate.