Pulsed Double-Electrode GMAW-Brazing for Joining of Aluminum to Steel

Double-electrode gas metal arc welding (DE-GMAW) is an innovative process that can reduce the heat input to workpieces and increase the energy needed to melt a given amount of wire. To join steel to aluminum for this study, the current in the DE-GMAW was pulsed to further reduce the heat input. This resulted in pulsed DE-GMAW, which can join steel to aluminum by brazing the steel and welding the aluminum. The resultant technology may thus also be referred to as double-electrode GMAW-brazing. In this paper, this novel method was demonstrated through both theoretical analysis and experimental investigation. Dissimilar materials, aluminum and steel, were joined and major parameters affecting the metal transfer in the pulsed DE-GMAW process, including bypass arc parameters and pulsing parameters, were analyzed. The strength of the resultant aluminum-steel joint samples was examined. It was found that the average shear tensile strength was about 144.85 MPa, and the maximum one was around 186.73 MPa, which was about 88.5% of the strength of the aluminum base material. Pulsed DE-GMAW can thus be considered as an alternative method for low-cost joining of aluminum to steel.