BEHAVIOUR LAWS OF HOMOGENIOUS HOT AND COLD ROLLING TECHNIQUES FOR ALUMINIUM

A mathematical model describing the rolling of the slabs which has been formulated. The present model estimates the optimal rolling schedule which gives the maximum through put (rolling rate) of the hot rolling line at Nassiriya's factory.The material's resistance to deformation varied at each pass, an expression which relates it to the strain rate, temperature and reduction has been developed. Furthermore the limitation of the slab's ductility on the rolling schedule has been taken into consideration.In order to select the most accurate theory to be used in the present model, three theories were selected, these are Sims, Alexander & Ford and Orowan's homogeneous theory. It is clear that Orowan's theory was the closest to the experimental results, this theory involves many assumptions which could affect the accuracy of the model.A comparison with the experimental results was also made to verify the accuracy of the model. The model results obtained for rolling load, temperature, total time and productivity show in general agreement with the measured results obtained from hot rolling mill.The testing results of samples taken from the final flat strip for (3003 and A4) aluminum alloys show that the ductility decreases with the increasing number of passes, at the same time the yield stress, ultimate tensile strength and hardness increases with the increasing number of passes.The simplicity or the model which makes it extremely useful for parametric studies in which the influence of rolling parameters can be investigated.