| 摘要 |
PURPOSE:To manufacture a spiral grooved tube at high speed by forming a straight groove parallel to the tube axis on the inner face of a metallic tube, softening this by heating, and taking up while twisting around the tube axis. CONSTITUTION:A long-sized metallic tube 1 is elongated between a floating plug 2 and a die 3 around it, and a straight groove parallel to the tube axis is formed on the inner face by a grooving plug 5 on which a projection 6 is cut. The tube 12' provided with the straight groove is softened by heating with an induction heating device 14 and led to a twisting area controlling device 15. The tube came out from the twisting area controlling device 15 is turned between there and the take-up shaft 18 of a winder 17 and becomes a spiral grooved tube. |
