Submerged-arc welding method of high-intensity steel thick plate for nuclear power

The invention relates to a submerged-arc welding method of a high-intensity steel thick plate for nuclear power. The submerged-arc welding method of the high-intensity steel thick plate for nuclear power includes the following steps that high-intensity steel is utilized, the Rm of the high-intensity steel is no less than 645Mpa, the ReL of the high-intensity steel is no less than 535Mpa, the ductility A of the high-intensity steel ranges from 20% to 40% and the -45oCKV2 ballistic work of the high-intensity steel is larger than 54J. Two plates with the same width ranging from 36mm to 48mm are combined and connected in an abutted mode. A matched welding stick has the tensile strength of more than 600MPa and the diameter of 4mm. U-shaped submerged-arc welding grooves are symmetric, the angles of the grooves are 60 degrees and the truncated edges are 6mm long. Under the condition that currents are 650A to 700A, the voltage is 33V to 31V, the rate is 45cm per minute to 35 cm per minute and linear energy is 31kJ per cm to 35kJ per cm, continuous welding is performed. The submerged-arc welding method of the high-intensity steel thick plate for nuclear power solves the problems that when steel thick plates with the tensile strength of no less than 585Mpa for a nuclear power (AP1000) pressure bearing device is welded, a submerged-arc welding butt joint is not pre-heated before welding and does not undergo heat treatment after welding in an existing welding technology method, the tensile strength and joint ballistic work of the submerged-arc welding joint reach high levels and the joint has high impact toughness reserve and high safety margin.