| 摘要 |
The invention concerns a method for manufacturing of square pipes from coated steel strips. Both sides of the strip are coated with metal, say zinc or aluminum. The strips also can be industrially painted e.g. with PVC-plastics directly upon the steel surface or upon the metal-coated surface. The shaping is carried out in a continuous roller shaping device by at first shaping a profile (6) with a bottom part (7) and side parts (8) equal to the finished pipe. The top parts (9) are made equal to half of the bottom part of the pipe and ended with foldings (5). The angle (11) between the bottom part (7) and the side parts (8) is made acute and the angle (12) between the side parts (8) and the top parts (9) is made obtuse. The facing coated surfaces (13) at the foldings (5) are heated by laser and compressed at the following roller shaping when the finished shape of the pipe is made. |
