Abstract: The contrast tests of hardness and impact toughness were performed with surfacing metals with two commercial flux-cored wires for die surfacing repair. The cause of performance difference was analyzed. The results show that the hardness and impact toughness of the surfacing metal with 525 welding wire were higher than those of the metal with 136 welding wire. The substrate microstructure of both the two surfacing metals was composed of martensite, bainite and ferrite. The grain size of surfacing metal with 525 welding wire was smaller. The area of fibre zone on impact fracture of the surfacing metal was large while more and smaller dimples were found in the metal with 525 wire. The reason for toughness difference of the two metals was brittle inclusion with large size existing in the microstructure of the surfacing metal with 136 melding wire.