Producing tubes from sheet material with varying thickness, comprises forming profile using die and punch, calibrating profile and joining together length edges to create tube

摘要

The process comprises the following steps: (A) forming a profile in a forming device comprising at least one die (1) and at least one punch (2), the die and/or punch being adapted to the change in material thickness; (B) calibrating the profile; and (C) joining together the opposing length edges of the sheet material (3) from which the profile is formed, in order to create a tube. Independent claims are also included for the following: (1) Apparatus for producing tubes by this process, comprising a forming device, a calibrating device and a welding device; and (2) Calibrating device for the external cross-section of a profile, comprising at least one set of forming rolls which at least partly span a plane corresponding to at least part of the external cross-section of the profile to be formed, and a means for keeping the opposing length edges of the sheet material at a predetermined distance apart.