The invention discloses a high-strength and high-tenacity gas shielded
welding wire. The
welding wire comprises the following
chemical composition in percentage by
mass: 0.02 to 0.12 percent of carbon (C), 1.20 to 2.10 percent of
manganese (Mn), 0.20 to 1.00 percent of
silicon (Si), less than or equal to 0.010 percent of
sulfur (S), less than or equal to 0.015 percent of
phosphorus (P), 2.00 to 3.50 percent of
nickel (Ni), 0.20 to 0.80 percent of
molybdenum (Mo), 0.20 to 0.30 percent of
titanium (Ti), 0.60 to 1.20 percent of
chromium (Cr), less than or equal to 0.05 percent of
vanadium (V), 0.005 to 0.010 percent of
boron (B), less than or equal to 0.015 percent of aluminum (Al), less than or equal to 0.35 percent of
copper (Cu) and the balance of iron (Fe). The
welding wire is used for welding steels of a strength grade of between 850 and 950MPa; and under the protection of a
mixed gas (80 percent of
argon (Ar) and 20 percent of
carbon dioxide (CO2)), the
weld metal tensile strength of the welding wire is more than or equal to 850MPa, the yield strength is more than or equal to 720MPa, the elongation is more than or equal to 22 percent, and the low-temperature
impact toughness Akv is more than or equal to 181J at the temperature of -30 DEG C, or more than or equal to 175J at the temperature of -40 DEG C, or more than or equal to 162J at the temperature of -50 DEG C.