METHOD OF PRODUCING SEAM-WELDED PIPE HAVING GOOD WELDED PORTION CHARACTERISTICS

摘要

A method of producing a seam-welded pipe having good welded portion characteristics with high efficiency which positively forms the shape of the opposite ends of the rounded width of a band material immediately before seam-welded into a desired tapered shape in response to a change in band material thickness flexibly to thereby retain a good weld quality. The method of producing a seam-welded pipe which molds a band material (20) and seam-welds it with its ends butt-joined to form a pipe (30), wherein a tapered shape is imparted, before the molding, to the above end on any one surface side of the upper and lower surfaces of the band material and to the facing end by means of cutting or grinding (3) or fin pass rolling (4).