Development of the innovative GMA wire improving the flow direction of molten pool

Abstract

As sulfur content increases in weld metals, hot cracking is likely to occur. Therefore, to prevent hot cracking, the sulfur content of the welding consumables is controlled to be as low as possible in general. On the other hand, sulfur can considerably reduce the surface tension of the molten iron. Utilizing the latter characteristics of sulfur, the authors have succeeded in the development of an innovative gas metal arc (GMA) welding wire that contains a higher amount of sulfur as compared with conventional wires and possesses the flowing characteristics of the molten pool more suitable for thin steel plate welding. It has also been found through this research that the hot crack resistance of the weld metal degraded by increasing sulfur can be canceled by decreasing the carbon content of the wire to a substantially low level. The newly developed wire offers the following advantages over conventional solid wires: (1) wider and more consistent bead shape, (2) less undercut at higher welding speeds, (3) easier setting of the welding conditions due to wider tolerability to voltage fluctuations, and (4) excellent paint adhesiveness due to less slag generation.