Influence of Minor Elements in Electrode Wire on Spattering Phenomena in CO₂ Gas Shielded Arc Welding

Abstract

Although CO₂ gas shielded arc welding is the mainstream arc welding method, a large amount of spatter is generated during welding. To solve this problem, the mode of spatter generation was elucidated and the influence of minor elements in the electrode wire on the amount of spatter generation was investigated, clarifying the following facts. In CO₂ gas shielded arc welding, because the arc generated at the suspended droplet is constricted and the arc point is violently displaced on the droplet surface, the droplet undergoes repeated irregular shaking as it is transferred to the molten pool. As a result, a large amount of spatter is generated by fragmentation of the droplet due to short-circuiting/re-arcing during droplet transfer, or by scattering of the droplet by the arc force. As countermeasures for this unstable droplet transfer, addition of Ti to the wire has the effect of suppressing short-circuiting by stabilizing the molten pool, while addition of K reduces the amount of spatter by stabilizing the arc. Conversely, addition of REM or Ca causes an increase in large-sized spatter due to extension of the arc and accompanying scattering of the droplet.