Effect of torch angle and position on bead geometry and joint strength during arc brazing of thin-gauge dual-phase steel

Gas metal arc brazing (GMAB) technology is a transformative non-fusion joining process used in the joining of thin-gauge advanced high strength steels (AHSSs) employed in the automotive industry. Due to its lower heat input capability, the technology offers several benefits over conventional gas-metal-arc welding (GMAW) process such as minimal Zn-coating burn-off, lower distortion, minimal welding defects, and a reduced heat-affected zone (HAZ). In this study, the effect of torch position and (work and push) angles on the location of droplet transfer, behavior of arc, resulting bead geometry, and the mechanical properties of lap joints have been investigated during GMAB of galvannealed DP600 using CuSi3Mn1 (i.e., Si-Bronze) filler wire. The results showed that the torch position and process angles have a significant effect on the location of the arc and the location of the droplet transfer, which impacts the geometry of the melt pool which controls the final bead geometry. Subsequently, it was shown that torch angle and position had a direct influence on the distribution of the heat input into the workpiece, as well as on the mechanical properties of the joint. As a result, this study offers detailed insights into the optimization of the arc-brazed joints by controlling the torch position and angle without changing the main processing parameters such as wire feed speed, travel speed, and voltage.