| 摘要 |
PROBLEM TO BE SOLVED: To provide a seam welding method capable of improving the low-temperature toughness of an electric resistance welded steel pipe seam with simple means.SOLUTION: An inclined surface is provided on an outer surface side of each edge portion of an open pipe 1, a depth h (mm) of the inclined surface is set to fall in a range from (1/5)t to (49/50)t with respect to a thickness t (mm) of the open pipe 1, an angle &thetas; formed between an end surface of each edge portion and the inclined surface is set to fall in a range from 15 to 60°, and the edge portions are welded while an L/V calculated by using a length L (m) of an interval from a position at which each edge portion is pressed by squeeze rolls 2 to a position at which the edge portions are welded and a transport velocity V (m/second) of the open pipe 1 is kept within a range from 0.05 to 0.20.SELECTED DRAWING: Figure 1 |
