Abstract
3003 alloy bare fins, the basic component for brazing application, were made with varying distribution of precipitates and amount of solution by changing homogenizing conditions and with varing strain by changing the final reduction ratio of cold rolling. These fins were submitted to a sag test, and the change in sag distance was investigated in relation to the structural change during heating. The sag is classified into two components; one is controlled by recovery and recrystallization and the other occurs in the temperature range 550-610°C without structural change after the completion of recrystallization. The former component occurs accompanied by the migration of dislocation and grain boundary. Thus, in the case where the driving force for recrystallization is small and the dragging force is large, the sag tends to be large as the recrystallization during heating continues to the elevated temperature, making the migration of dislocation and grain boundary easy. The latter component which advances without structural change is caused by creep. Therefore, when the driving force is large and the dragging force is small, grain size becomes smaller, leading to a larger sag.
