| 摘要 |
PROBLEM TO BE SOLVED: To provide a plasma key hole circumferential welding of a metal tube capable of obtaining a weld joint in which any defective welds attributable to gas trap are not present in a bead terminal overlapping part after the crater fill. SOLUTION: In this method, the crater fill is performed by adjusting the shield gas atmosphere so that the oxygen concentration in a weld metal after the crater fill part is solidified is 0.005-0.02 mass %.
|
