| 摘要 |
Provided is a method of forming a welded portion of a pipe, which has an excellent corrosion resistance, including the steps of welding a pipe using a welding material applied to an inner welded portion of the pipe, of which the strength is within an error range of±5% relative to the strength of a base material, and a welding material applied to an outer welded portion of the pipe, of which the strength is within an error range of 5 to 15% relative to the strength of the base material when manufacturing the pipe; and expanding the welded pipe. Therefore, the excellent corrosion resistance for the high-strength steel pipe can be secured, and controlling the strength of the inner welded portion by appropriately controlling the tube enlarging rate is possible. |
