Abstract: The developed wires were used for gas metal arc welding. The chemical composition, microstructure, tensile strength and corrosive pitting rate of weld bead and Rockwell hardness, bend strength and impact toughness of welded joint were investigated. The microstructure of weld metal was analyzed by metalloscope. The impact fracture was analyzed by scanning electron microscope, and inclusions of impact fracture were analyzed by energy spectrometer. Experiment results indicated that it was effective to add rational nickel and MnN in the wire to accelerate austenite formation. The influence factors of pitting corrosion resistance and impact ductility were studied. It had been found that, besides chemical constitution, the uniform distribution of duplex phases in the weld metal could improve pitting corrosion resistance. Elements Mn, Ni, Cr etc. were the assurance of welded joint impact ductility.