Method of manufacturing electric resistance welding pipe having excellent characterization of welded seam

A method of manufacturing an electric resistance welding pipe having excellent characterization of welded seam, comprising:

• subjecting a strip to forming such that longitudinally extending edges substantially face each other;
• shaping by tapering the longitudinally extending edges at either of top and bottom sides of the strip, or the longitudinally extending edges at both of the top and bottom sides of the strip, wherein an angle from a surface of the longitudinally extending edge toward vertical direction is in a range of 25 degrees to 50 degrees and a length of a perpendicular from starting position to end position shaped by the tapering at one side is 20% to 45% of thickness and wherein edges at an inner surface side of the strip are shaped with tapering in a first stage of finpass tapering and edges at an outer surface side of the strip are shaped with tapering in a second stage of finpass tapering;
• and
• welding the longitudinally extending edges by electric resistance welding to form a pipe.