| 摘要 |
PURPOSE:To prevent the generation of welding defects on edge seams and to improve the productivity in manufacture of a spiral pipe from a steel hoop by feeding the hoop to a forming bed by a means of a hoop looper provided in the line of a charging bed. CONSTITUTION:A steel hoop placed on a charging side bed 7 of a spiral pipe manufacturing device is passed on a hoop guide table 14 by a prescribed length, and is wound around a looper car 16 by folding back with a bending roll 15 mounted on the delivery side of the device, and is wound in a Z-shaped manner through bending rolls 17, 18 to generate a tension opposing to the tension caused by the looper car 16. Next, the hoop delivered from the roll 18 is passed through the 2nd pinch roll 5B and a preforming roll 6 and is formed into a spirally wound pipe by a roll bender 8 on a forming bed 10 to produce a spiral steel tube. |
