| 摘要 |
PURPOSE:To enable variegated patterning of the surface of a pipe by a single process, by a method wherein a rotary mold is arranged so that a roll surface having a sectional form obtained by dividing a circle, whose diameter is the same as the outside diameter of a work pipe or smaller than that, into at least two is positioned on the same circumference. CONSTITUTION:A groove of a roll has a sectional form obtained by dividing a circle, whose diameter is the same as the outside diameter of a work pipe or a little smaller than that, into at least two arcs. To position roll surfaces each on the same circumference four rotary molds 31-34 are arranged on all sides so that they abut against an outer circumference of a work pipe 10. The work pipe 10 is passed through between heater 23 by a feed roll 21, the surface of the work pipe 10 is preheated at the softening point or higher and sent into a tie-dying processing device. The work pipe 10 is fed forward by a rotation of the rotary mold while the whole circumference is abutting against roll surfaces of the four rotary molds 31-34. A variegated is formed on the surface of the pipe 10. |
