PIPE JOINT WELDING METHOD USING PLASMA WELDING PRIOR TO CO2 WELDING IN COMBINATION AND JOINT PIPE WELDED BY SUCH METHOD

To provide a pipe joint welding method using plasma welding preceding CO2 welding which performs pipe welding joint by plasma welding in combination, prior to CO2 welding in pipe joint welding.SOLUTION: A pipe joint welding method using plasma welding in combination preceding CO2 welding includes steps of: tightly adhering a pipe end of an elbow 2 to a pipe 1 to be processed for tacking them together and then fixing the pipe end to a chuck for attaching a welding robot; performing sealing welding 5 onto a welding line whole circumference of the pipe 1 to be processed and the elbow 2 to be welded to the pipe by using a welding torch of a plasma welding machine; performing keyhole welding 6 of the whole circumference of sealing welding 5 portion between the pipe 1 to be processed and the elbow 2; and performing bulging welding 7, 8 according to CO2 welding over the whole circumference of the keyhole welding 6 portion between the pipe 1 to be processed and the elbow 2.SELECTED DRAWING: Figure 1 【課題】管接合溶接におけるＣＯ2溶接に先立ち、プラズマ溶接にて管溶接接合を行うＣＯ2溶接に先んじるプラズマ溶接を併用する管接合溶接方法を提供する。【解決手段】被処理管１にエルボ２の管端を密着して仮付けし、溶接ロボットの取り付け用チャックに固定する工程と、プラズマ溶接機で被処理管１とこれに接合するエルボ２の溶接線全周に、プラズマ溶接機の溶接トーチでシーリング溶接５を行う工程と、被処理管１とエルボ２との間のシーリング溶接５部分の全周をキーホール溶接６を行う工程と、被処理管１とエルボ２との間のキーホール溶接６箇所を全周に渡りＣＯ2溶接による盛り上げ溶接７，８を行う工程と、を有するＣＯ2溶接に先んじるプラズマ溶接を併用する管接合溶接方法。【選択図】図１