Lately modern hardfacing tubular wires for semiautomatic welding with gas protection and without it have been developed. These wires deposit Fe-based nanostructured alloys with high abrasive wear resistance. The information on these new consumables is scarce, especially about the effect that the welding parameters (heat input, shielding gas, arc voltage, current intensity, etc.) have on the deposit, its microstructure and, consequently, its wear behavior. For this reason, in this work it was studied the effect of heat input (voltage, intensity of current and welding velocity) on the properties of a FCAW Fe-based nanostructured deposit obtained without gas protection. This study is a continuation of a previous one in which the same consumable was used under shielding gas. Bead on plate samples were welded using heat inputs between 0.5 and 3.5 kJ/mm. The dimensional study was performed on the beads, chemical composition was determined and the microstructure was analyzed using optical and electronic microscopy and X Ray diffraction. Microhardness, cristalita size and dilution percentage were also measured. It was observed an important influence of the welding parameters on the bead geometry and the microstructure. The operational behavior of this wire, welded without shielding gas, was very good.
hardfacing deposits; open arc wire; nanomaterials; heat input; microstructure
