| 摘要 |
The beam, which preferably has a U-shaped cross-section, is produced by profiled forming of flat, identical width sheet metal that has previously had its length edges (A, B) subjected to a rolling or rolling/wear process in order to eliminate undesired internal stress. Prior to profiled forming, the length edges of the sheet are progressively heated using e.g. induction heating in order to eliminate or substantially reduce internal stress. |
