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

摘要

A method of efficiently manufacturing electric resistance welding pipes having excellent characterization of welded seams is provided, by which each lateral edge of a rounded strip immediately before electric resistance welding is securely shaped with desired tapering flexibly in response to change in strip thickness, so that welding quality may be kept to be excellent. A method of manufacturing electric resistance welding pipes, in which a strip 20 is subjected to forming, then edges thereof are confronted, and then the edges are subjected to electric resistance welding to form a pipe 30, includes a process that an edge and an edge opposed thereto at one of an upper-surface side and a lower-surface side of the strip are shaped with tapering before the forming by means of cutting or shaving 3, or finpass forming 4.