| 摘要 |
PROBLEM TO BE SOLVED: To perform multi-layer pad welding by complete melting and free from high temperature cracking for a welded structure of an X-shaped groove joint. SOLUTION: While forming a groove angleθwithin a range of 30 to 40 degrees and setting high current pulse welding wave-forms, a plurality of mean current of every gap width range to be outputted at an initial layer welding and other mean currents at a filling layer and a finish layer, and when the initial layer welding is performed, a mean current of as much as 300A at most is outputted having the gap width of the groove part of 0 mm or the vicinity thereof. As the gap width is increased, the mean current value to be outputted is decreased stepwise by a degree of 20 to 40A and a mean voltage appropriate for the mean current is calculated and outputted. The welding area Sna to be welded and the welding speed Vw corresponding to the gap width are calculated to conduct the increase/decrease control. When the filling layer and the finish layer are welded, a mean current and a mean voltage of a predetermined value are outputted to calculate the welding area Sna and the welding speed Vw based on the deviation of the bead width of the previous layer or the gap width to conduct the increase/decrease control. COPYRIGHT: (C)2003,JPO
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