A swing arc narrow gap gas metal arc welding process assisted by direct-current hot wire

To improve the practicability and efficiency of thick-steel narrow gap gas metal arc welding, a novel swing arc narrow gap welding process is developed by integrating a non-swaying direct-current hot wire. The swing arc deflection behaviours and the metal transfer phenomena are then investigated at the different polarities and currents of the hot wire. By measuring the central-region microhardness distribution and penetrated area of the weld bottom, the approaches of evaluating the weld microstructure homogeneity and the welding efficiency potential are proposed, respectively. Experimental results show that the hot wire process with the direct current electrode positive polarity yields higher welding efficiency potential by 54.8% than the other direct-current hot wire process, while obtaining good process stability and sound weld formation.