FCB submerged-arc welding method for unequal-thickness jointed boards

The invention relates to the technical field of shipbuilding, and discloses an FCB submerged-arc welding method for unequal-thickness jointed boards. The FCB submerged-arc welding method comprises thefollowing steps that S1, the opening angle of a groove and the height of a truncated edge are determined according to the thickness of a thin board, and grooves are machined in the thin board and a thick board; S2, the top end of the groove of the thick board is chamfered, and the bottom end of a bevel is flush with the top end of the thin board; S3, the thick board and the thin board are arranged on an assembling station, the thick board is flush with the side, deviating from the groove, of the thin board, and the truncated edges of the grooves are tightly attached; and S4, the center of a copper gasket is aligned with the center of the groove, the copper gasket is tightly attached to the back faces of the thick board and the thin board, and submerged-arc welding is conducted on the groove. The opening angle of