TWO-ELECTRODE SUBMERGED ARC WELDING METHOD FOR SQUARE JOINT

摘要

PROBLEM TO BE SOLVED: To obtain a uniform bead shape and a sound weld zone over the whole length of a weld line by inclining the object to be welded into the specified angle or less so as to become descending slope welding and specifying the inclined angle of a preceding electrode and the inclined angle of a succeeding electrode. SOLUTION: The excessive penetration and depth are prevented, the too small bead depth is avoided and the crack due to high temperature and the groove incomplete fusion are hardly generated by inclining the object A to be welded into 3 deg. or less so as to become a descending slope. The inclined angleθL of the preceding electrode L is specified to be the sweepback angle of 15 deg.-35 deg.. WhenθL is less than 15 deg., since the action pushing the molten metal and molten slag backward by the arc of the preceding electrode L is insufficient and the molten metal and molten slag flow into just under the arc, slag inclusive is generated and the lack of uniformity on the bead depth and the height of reinforcement of weld are generated. The inclined angleθT is specified to be the sweepback angle of 10 deg.-30 deg.. WhenθT is less than 10 deg., the excessive bead width and the insufficient height of reinforcement of weld are not dissolved.