Effect of the Content of Graphite in the Slag Powder of the Steel LRF on the Microstructure and Properties of SAW of Ductile Iron

The use of protective powders in submerged arc welding (SAW) is one of the methods for protecting the Welding pool. In this research, it has been attempted to use ladle refining furnaces (LRF) slag as an alternative to a ductile cast iron shielding powder. For this purpose, the hardness and maximum tensile strength of the ductile iron before and after the SAW with protective powders including from 0 to 25 wt% of graphite and 100 to 75 wt% of the LRF slag powder have been compared. The results show that the welding quality is improved by increasing the amount of graphite powder in the powder of the LRF, because the maximum tensile strength of the welded metal is nearly the maximum tensile strength of the non-welded cast iron (control specimen). Also, the amount of graphite powder in the slag powder of the LRF has the straight relation with the hardness of the welding metal.