| 摘要 |
Welds (111a) are provided in areas that are offset from curved portions (111b) where stress concentration is likely to occur. This allows excess stress to be inhibited to occur at the welds at the time of tube enlargement. Therefore, even if the welds are softened and proof stress (mechanical strength) is reduced at the time of welding, as the stress occurring at the welds at the time of the tube enlargement can be prevented from exceeding the proof stress (allowable stress) of the welds, the welded tubes can be adopted in a radiator in which the tubes (111) and the fins (112) are joined together mechanically by tube enlargement. As a result, the manufacturing cost of the tubes can be reduced in comparison with the case when seamless tubes are adopted as the tubes. <IMAGE> |
