Method of submerged arc welding of high tension steel workpieces

A method of submerged arc welding a workpiece of high tension steel with a tensile strength of at least 60 Kg/mm.sup.2, comprising the steps of

• covering a weld joint of the workpiece with bonded flux containing carbonate capable of generating at least 7 percent by weight of carbon dioxide gas, based on the total weight of the flux, during the welding operation and producing slag with a basicity of not smaller than 1.0;
• placing a welding wire in the proximity of said weld joint through said flux, said welding wire consisting essentially of 0.3 to 1.4 percent by weight of silicon, 0.3 to 3 percent by weight of manganese, 0.1 to 1.7 percent by weight of chromium, 0.1 to 1.10 percent by weight of molybdenum, and substantially the remainder of iron;
• applying a welding voltage to the welding wire so as to feed a welding current to said weld joint through said welding wire while moving said welding wire relative to said weld joint, so as to generate high tension weld metal in the weld joint by submerged arc welding having a high toughness and a high crackresistivity;
• said carbon dioxide gas and said slag with a basicity of not smaller than 1.0 being provided by forming said bonded flux with up to 60 percent by weight of at least one carbonate selected from the group consisting of calcium carbonate, magnesium carbonate, sodium carbonate, barium carbonate, manganese carbonate, 4 to 16 percent by weight of silicon dioxide, 8 to 24 percent by weight of alumina, and the remainder of at least one compound selected from the group consisting of calcium oxide and magnesium oxide;
• said weld metal consisting essentially of 0.04 to 0.07 percent by weight of carbon, 0.2 to 0.8 percent by weight of silicon, 1 to 1.8 percent by weight of manganese, 0.15 to 0.9 percent by weight of molybdenum, 0.1 to 1.5 percent by weight of chromium, 0.1 to 3.5 percent by weight of nickel, and substantially the remainder of iron, the steel of said workpiece containing 0.06 to 0.25 percent by weight of carbon, 0.01 to 0.55 percent by weight of silicon, 0.40 to 1.60 percent by weight of manganese, 0.01 to 0.50 percent by weight of copper, 0.01 to 2.50 percent by weight of nickel, 0.01 to 1.50 percent by weight of chromium, less than 1.00 percent by weight of molybdenum, 0.01 to 0.09 percent by weight of aluminum, less than 0.15 percent by weight of vanadium, less than 0.005 percent by weight of boron, less than 0.10 percent by weight of titanium, and less than 0.05 percent by weight of niobium.