SHIPBUILDING 5NI STEEL SUBMERGED ARC WELDING METHOD

The present invention relates to a submerged arc welding method of 5Ni steel for shipbuilding, comprising: (1) using 5Ni steel with a tensile strength of 630-670 MPa as base material for splicing, wherein the to-be-spliced base material has a transverse impact toughness value of ≥ 180 J at -130 °C; a matching welding material is, a welding material with a tensile strength of 630-710 MPa, wherein a welding wire has a diameter of Φ2.4 mm or more and belongs to a product model of INCO-WELD Filler Metal C-276, and a flux is INCOFLUX 9; (2) the to-be-spliced material uses a K-shaped groove as groove for the submerged arc welding; (3) welding parameters: welding current is 410±10 A, welding voltage is 32±1 V, welding speed is 27±2 cm/min, welding energy is 30±3 KJ/cm; continuously welding abutting joints of to-be-spliced base materials wherein the base materials have the same plate thickness, until the weld seam is filled; after each pass of welding, using a wire brush to clean weld bead; a flux baking is performed at 350°C×1h; an interpass temperature is controlled to be ≤ 80°C. The tensile strength and impact absorbed energy value (at weld seam, fusion line, heat-affected zone, etc.) of the submerged-arc-butt-welded joints have reached a high level, and the welded joints have excellent impact toughness at a low temperature and excellent cold bending performance.