The aim of this master thesis is to investigate the influence of different rolling parameters on the AA8079 alloy as well as the influence of various hot strips on cold rolling. The microstructure development and softening behavior of the material is investigated in detail. Different rolled strips produced by the AMAG company by hot rolling, which showed significant dissimilarities in grain size and degree of recrystallization, were used during the laboratory tests. A significant influence of the hot-rolled strips was reflected in the hardening and softening behavior. The goal was to investigate the effects on the material properties. The samples from these cold rolling tests were annealed at various temperatures to reveal the softening behavior of the AA8079 alloy. The acquired knowledge was used to provide guidance for the industrial tests that followed. The laboratory tests also included investigations of dynamic recovery. It was checked, if a change in the number of rolling passes, of the same degree of total deformation, affects the characteristic values. In this research no noticeable influence was observed, but it was shown that temperature was a crucial factor for the extent of dynamic recovery. In the industrial tests, parameters such as rolling speed and starting temperature were changed to investigate their influence on cold rolling. The obtained samples were annealed at various temperatures and holding times. Based on the results, it is obvious how important the starting temperature for the dynamic recovery is. If it is increased from 30 °C to 70 °C, a significant difference in the resulting strength is visible. With the material from the industrial tests, an intermediate annealing of the material was carried out to mimick the industrial process in the laboratory. The results showed no dissimilarity in conductivity for annealing temperatures up to 330 °C and 450 °C. These samples were cooled down slowly (25 K/h) afterwards. Because of this, an effect of the different annealing temperatures was no longer recognizable after cooling.
|Translated title of the contribution
|Influence of cold rolling on microstructure development and the resulting softening behavior of AA 8079 foil-stock
|31 Mar 2023
|Published - 2023
Bibliographical noteembargoed until 14-02-2028