| 摘要 |
PURPOSE:To obtain a metallic pipe having desired shape such as a square pipe etc. using a simple device by forming a metallic strip into cylindrical form, welding butted parts, putting it in a forming die and applying pressure from inside. CONSTITUTION:A metallic strip 2 is supplied continuously to a cylinder forming device 4 consisting of plural roll groups 4a and formed into cylindrical form. Tw o side edges of the metallic strip 2 are butt welded by a welding torch 6 and a circular pipe 9 is formed. This circular pipe 9 is put in a forming die 5 and held between an upper die 5a and a lower die 5b. Pressure is applied in the circular pipe 9 and formed into desired shape bringing the outer face of the circular pipe 9 into close contact with the inner face of the forming die 5. In this way, a metallic pipe for a square metallic gutter etc. can be manufactured easily. |
