| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a steel pipe for reinforcing the ground, which can be obtained by efficient machining work, and a method of manufacturing the same. <P>SOLUTION: In the steel pipe 10 for reinforcing the ground, which has approximately a cylindrical shape, spiral grooves 13 formed on the outer peripheral surface 12 of the pipe matched with diameter reduction by drawing, are continuously formed in the longitudinal direction. When manufacturing the steel pipe 10 for reinforcing the ground, by using a drawing die 53 on the inner peripheral surface 15 of which protrusions 532 are formed and which are provided rotatably and drawing a cylindrical workpiece 100 out of the inside of the drawing die 53, the diameter of the workpiece 100 is reduced and also the spiral grooves 13 are formed on the outer peripheral surface 12 of the workpiece 100 by the rotation of the drawing die 53. <P>COPYRIGHT: (C)2013,JPO&INPIT |
