Abstract
There are many investigations on recrystallization of cold rolled aluminium sheets, but few on recrystallization phenomena of cold bent one. But forming occupies the greater parts in cold forming works and when such a bent material is heated in working or using, the metallurgical defects have frequently appeared. Nevertheless, probably nothing has been reported on the investigations which studies systimatically how to prevent from these accidents. This is a study on the changes of macrostructure and dimension of cold bent aluminium which take place through successive isothermal annealing. The findings are summarized as follows:
The appearances of recrystallized grain in the longitudinal section almost correspond with the stress distribution diagram induced from stress-strain curve.
Under low temperature annealing, there is a slight change in curvature of bending and the magnitude of shrinking in dimention increases remarkably caused by recrystallization on strain field below the value near 0.10. But when these samples are heated at temperature higher than 480°C, large shrinking in dimension and coarse grain in the longitudinal section take place, to which attention must be paid in practice.
