Enhancement of mechanical properties of low carbon steel joints via graphene addition

Steel base metal laps or welding electrode surfaces were coated using graphene suspensions with various concentrations, and then the steel plates were welded using the shielded metal arc welding process. Microstructural observations showed that the addition of graphene to the weldment significantly refines the microstructure and promotes the formation of fine acicular ferrite. The results of mechanical testing indicated that with lower concentrations of graphene in the weldment, both the strength and ductility improve, but the hardness remains unchanged in comparison to the unreinforced weld metal. However, reinforcing with a higher concentration of graphene gives rise to the significant enhancement of the hardness and strength without deterioration of the ductility.