| 摘要 |
<p>The tube consists of a strip of flat material, the edges of which are bent together by rolling deformation and are welded to one another from outside. In order that an extremely thin flat material strip can be used for the tube and a tube with a very attractive exterior is produced, the flat material strip is provided with at least one wear layer and its edges are welded using radiation energy in a manner known per se.</p> |
