| 摘要 |
Conventional electric resistance welded steel pipes cannot always ensure fatigue resistance required as drive shafts. In detail, a base material portion of an electric resistance welded steel pipe has a composition including C at 0.25 to 0.55%, Si at 0.01 to 1.0%, Mn at 0.2 to 3.0%, Al at not more than 0.1% and N at 0.0010 to 0.0100%, with the balance being represented by Fe and inevitable impurities, and the weld defect area, which is a projected area of a weld defect in an electric resistance weld zone, is less than 40000 µm 2 . |
