METHOD FOR REPAIRING POOR WELD ZONE OF METAL CASK WELD STRUCTURE AND METAL CASK PROVIDED WITH HEAT TRANSFER COPPER FINS

PROBLEM TO BE SOLVED: To provide a method for repairing a poor weld zone of a metal cask weld structure and a metal cask provided with heat transfer fins capable of ensuring excellent repair weldability of a poor weld zone, ensuring the elimination of the poor weld zone such as an excessive undercut or an insufficient throat by unique repair work, and obtaining a high-quality repaired weld bead and a high-quality repaired cross-sectional part.SOLUTION: A method for repairing a poor weld zone of a metal cask weld structure, comprises performing repair welding for thickening a poor weld zone generated in the course of welding a plurality of heat transfer copper fins made of copper and disposed to be inclined between a copper inner cylinder and a copper outer cylinder disposed outside of the inner cylinder or a poor weld zone detected in a quality inspection process after welding, from above a weld bead part having the poor weld zone, by using a weld torch identical to or similar in type to a TIG-MIG weld torch or a MIG weld torch used in a welding process and a weld wire and shield gas identical in component as a weld wire and shield gas used in the welding process, traveling the TIG-MIG weld torch or the MIG weld torch in the same direction as the weld direction at the time of work in the weld process, and performing composite welding that is a combination of preceding TIG welding and subsequent MIG welding.SELECTED DRAWING: Figure 16 【課題】溶接不良部の補修溶接性に優れ、独自の補修施工によってアンダーカット過大やのど厚不足等の溶接不良部を確実に消滅させ、品質良好な補修溶接ビード及び補修断面部を提供する。【解決手段】金属キャスク溶接構造物の溶接不良部補修方法は、鋼製の内筒と、該内筒の外側に配置される鋼製の外筒との間に傾斜配備される銅製の複数の伝熱銅フィンを溶接する過程で発生する溶接不良部、又は溶接後の品質検査工程で検出される溶接不良部を、溶接工程で使用したＴＩＧ−ＭＩＧ溶接トーチ又はＭＩＧ溶接トーチと同一又は同種の溶接トーチ、同一成分の溶接ワイヤ及びシールドガスを使用し、溶接工程で施工した時の溶接方向と同一方向にＴＩＧ−ＭＩＧ溶接トーチ又はＭＩＧ溶接トーチを走行させ、先行ＴＩＧと後続ＭＩＧとの複合溶接又はＭＩＧ溶接によって、溶接不良部を有する溶接ビード部の上から肉盛するように補修溶接を施工する。【選択図】図１６