| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the following problem: drawing for a welding position is troublesome in a backing strip fitting-welded to an inner hole of a square steel pipe; and welding gets defective or like in accompaniment to a fusion material volume change caused by variation of a projected length, when welded projectedly by a fixed length from a cut end of the square steel pipe, without depending on eye estimation of a worker. <P>SOLUTION: The backing strip fitting 4 is held by a holder 5, to go along an inner hole side face of the one-side square steel pipe, and to project an upper end a little from an inner hole cut end face of the one-side square steel pipe, in a method of welding-joining integrally the upper and lower square steel pipes and a metallic wide intermediate sheet 3, while interposing metallic wide intermediate sheet 3 between the upper and lower square steel pipes, then the holder is removed after welding a lower end of the backing strip fitting onto the inner hole side face of the one-side square steel pipe, and the intermediate sheet is mounted on a projected end part of the backing strip fitting, to weld a space between the intermediate sheet and the inner hole cut end face of the one-side square steel pipe, and the other side square steel pipe of the upper and lower square steel pipes mounted on the insert sheet. <P>COPYRIGHT: (C)2012,JPO&INPIT |
