| 摘要 |
PROBLEM TO BE SOLVED: To provide a pipeline in which the low temperature toughness of a circumferential weld metal part is excellent in a circumferential direction, and to provide a circumferential electron beam welding method of steel pipes. SOLUTION: In the pipeline, the circumferential weld metal part of a steel pipe obtained by welding steel pipes in a circumferential direction by electron beam welding contains, by mass, 0.005 to 0.020% solid solution Ti and 0.0015 to 0.0060% solid solution N. In the electron beam circumferential welding method for steel pipes, as for the cooling rate of the circumferential weld metal part, the cooling time from 800 to 500°C is controlled to≤5 s, and the cooling time from 500 to 300°C is controlled to 2 to 10 s; and the content of solid solution Ti in the circumferential weld metal part is controlled to, by mass, 0.005 to 0.020%, and the content of solid solution N is controlled to 0.0015 to 0.0060%. COPYRIGHT: (C)2004,JPO |
