JPS5493652A - Method and apparatus for manufacture of crossed pipe parts - Google Patents

Abstract

PURPOSE: To make small the variation of the curve and to make possible the automatic welding, by dividing the intersectional curve at the welded joint portion of pipes into four sections, and by simultaneously welding one of four curve sections with the opposite curve section being not adjoining to the former.

CONSTITUTION: In the intersectional curve of the joint portion between pipes 1 and 2, the curve section from the point P₁ to the point P₆ is welded by the torch 7, which goes forward in the direction X at the horizontal posture 45 degrees inclining against the line O₁-O₁ including the center line of the pipe 1, and begins the welding at the point P₁, and continues welding along X₁ down to the point P₆, only tracing in the directions X and Y. At the same time, the torch 8 parallel to the torch 7 welds the curve section ranging from P₇ to P'₆ along X₃. During this period, torches 9 and 10 are at waiting state. When the welding for X₁ and X₃ is finished, torches 7 and 8 retreat, and torches 9 and 10 perform welding along respectively X₄ and X₂, tracing the X' axis and Y axis. The welding for pipes 1 and 3 is simultaneously performed by similarly dividing the weld zone into four sections; hereby, the variation of the curve is made small, and the automatic welding becomes possible.

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