| 摘要 |
PURPOSE:To successively manufacture a composite pipe for motorcar exhaustion which has superior heat-insulating and heat-retaining properties by electrically seaming a mild band steel into a pipe, forming a heat-insulating layer around its external surface, electrically seaming and welding a stainless band steel, etc., to the outside of the layer, and reducing the diameter. CONSTITUTION:Bandlike mild steel 1a uncoiled from an uncoiler 1A is formed into a pipe shape by a train of forming rolls 5, and electrically seamed and welded by a high-frequency coil 6 to manufacture an internal pipe 1. After the internal pipe 1 is covered with a bandlike heat-insulating material 2a such as ceramic in a pipe shape, butt parts at both ends are fixed with an adhesive tape 16. This internal pipe 18 with the heat-insulating material coating is covered with a stainless band steel 3a, and the connection part is electrically seamed and welded by a high-frequency welding machine 23 to obtain an external pipe. This composite pipe is reduced in diameter by a roller group 29 for diameter reduction to obtain a composite pipe 30. Thus, an exhaust gap pipe for a motorcar which consists of the internal pipe 1 having the interposed heat-insulating layer 2 and the external pipe 3 is manufactured successively. |
