| 摘要 |
<p>The quantity of S contained in designing steel component is reduced, a stretch reducer makes a rolling roll to have a hole type profile closer to a true circle in sizing rolling, and a pipe is made to have an appropriate profile ratio (ratio between the radius of curvature of the inner surface and the average inner radius) at the position corresponding to an edge portion. Even when the inner surface of a blank pipe subjected to sizing rolling is creased, a predetermined thickness workability is ensured in subsequent cold elongation, and therefore the pipe is applicable as a drive shaft for an automobile and can be used as a high strength hollow member excellent in fatigue strength and most suitable for reducing the weight and ensuring silence. Consequently, a drive shaft for an automobile can be produced inexpensively and efficiently.</p> |
