| 摘要 |
The tube to be produced consists of a wear-resistant internal tube (1) and a shock-resistant external tube. The internal tube (1) is prefabricated. The external tube is made from an initial pre-curved metal sheet (2), made by bending around the internal tube (1) and welded on the longitudinal adjacent edges (3). Shaping of the external tube around the internal tube (1) is effected by means of tools (4) which are pressed against the initial metal sheet (2). The parts of the tools are directly placed on the initial metal sheet (2) on at least three lines (5) distributed around the circumference and extending longitudinally over the length of the tube. Using the parts of the tools (4), the clamping force is applied to the initial metal sheet (2) perpendicularly or parallel to the gap between the edges (3) of said metal sheet (2) placed around the internal tube (1). |
