Improving the toughness of high strength GMA welds

The propertied of high strength GMA welds are controlled by bead size, in particular the weld metal microstructure which is controlled by weld cooling rate. Shielding gas composition is known to be important as regards the protection of the molten weld pool from atmospheric contamination. However the role of the shielding gas composition in developing weld metal toughness is less well documented. This paper attempts to identify those characteristics in the deposition of a weld which contribute to improved toughness in high strength steel welds.