| 摘要 |
The radiator has flat tubes (2), the ends (4) of which have a double step in at least one long side (6). One step is produced by an upsetting and widening process, and the other by cutting and bending. This involves widening the small diameter of the flat tube and decreasing its large diameter, and making a cut (8) in the narrow side (11) of the ends within the deformation sector (12). |
