Abstract: Plate members 17 are respectively rested on first and second tables IA and IB relatively movable toward and away from each other. The plate members 17 are caused to abut against reference positioning members 16a and 16b of reference positioning devices protruded ahead of and over opposing ends 1? of the tables IA and IB so that opposing ends of the plate members 17 are positioned in protrusion ahead of the opposing ends 1? of the tables IA and IB, and the plate members 17 are positioned laterally. Then, the positioned plate members 17 are locked on the tables IA and IB. After the reference positioning devices are retracted, the tables IA and IB are relatively moved toward each other to cause the opposing ends of the plate members 17 to abut together for formation of weld line X.

Abstract: Plate members 17 are respectively rested on first and second tables 1A and 1B relatively movable toward and away from each other. The plate members 17 are caused to abut against reference positioning members 16a and 16b of reference positioning devices protruded ahead of and over opposing ends 1? of the tables 1A and 1B so that opposing ends of the plate members 17 are positioned ahead of the opposing ends 1? of the tables 1A and 1B, and the plate members 17 are positioned laterally. Then, the positioned plate members 17 are locked on the tables 1A and 1B. After the reference positioning devices are retracted, the tables 1A and 1B are relatively moved toward each other to cause the opposing ends of the plate members 17 to abut together for formation of weld line X.

Abstract: It is made possible to position plate members to be butt-welded for formation of weld line in a small amount of time so as to enhance working capacity of butt welding. Plate members 17 are respectively rested on first and second tables 1A and 1B relatively movable toward and away from each other. The plate members 17 are caused to abut against reference positioning members 16a and 16b of reference positioning devices protruded ahead of and over opposing ends 1? of the tables 1A and 1B so that opposing ends of the plate members 17 are positioned in protrusion ahead of the opposing ends 1? of the tables 1A and 1B, and the plate members 17 are positioned laterally. Then, the positioned plate members 17 are locked on the tables 1A and 1B. After the reference positioning devices are retracted, the tables 1A and 1B are relatively moved toward each other to cause the opposing ends of the plate members 17 to abut together for formation of weld line X.

Abstract: It is made possible to position plate members to be butt-welded for formation of weld line in a small amount of time so as to enhance working capacity of butt welding. Plate members 17 are respectively rested on first and second tables 1A and 1B relatively movable toward and away from each other. The plate members 17 are caused to abut against reference positioning members 16a and 16b of reference positioning devices protruded ahead of and over opposing ends 1? of the tables 1A and 1B so that opposing ends of the plate members 17 are positioned in protrusion ahead of the opposing ends 1? of the tables 1A and 1B, and the plate members 17 are positioned laterally. Then, the positioned plate members 17 are locked on the tables 1A and 1B. After the reference positioning devices are retracted, the tables 1A and 1B are relatively moved toward each other to cause the opposing ends of the plate members 17 to abut together for formation of weld line X.