A Study on the Effect of Wire Composition on Welding with Gap and Offset in Cold Metal Transfer (CMT) GMAW

In this paper, weldability of cold metal transfer (CMT) gas metal arc welding is studied for welding conditions with gap and offset for two different wire composition and strength. The two wires used have different surface tensions and viscosities due to the presence of differing amounts of sulfur and titanium, respectively. The difference in strength is induced mechanically during the wire drawing process. Surface tension and viscosity directly result in the wettability of molten metal, which in turn affects the gap bridging and weldability with offset. Experiments suggest that high viscosity and surface tension result in weld bead with higher elevation and a better gap-bridging ability. However, low viscosity and surface tension result in better wettability, which leads to better weldability with a higher offset. The understanding derived from this research can facilitate the development of welding consumables suitable for welding conditions with various offset and gaps.