Influence of forming parameters on the final subgrain size during hot rolling of aluminium alloys

In this paper, the influence of rolling parameters (i.e. the slab temperature, roll speed, roll temperature and the ratio of the mean thickness to the contact length in the roll gap Hm/L) on the subgrain size is studied by the combination of finite element method (FEM) with the Taguchi experimental method. The FEM is first applied to simulate two existing single pass laboratory rolling schedules. The predicted distribution of subgrain size through the thickness agrees well with measurements. Then, the Taguchi method is applied to design an orthogonal experimental table, L9(34). A total of 9 virtual experiments are analysed by the use of FEM. The predicted results are then analysed by the use of the Taguchi method from which the influence of each rolling parameter on the deformed subgrain size is given and expressed in percentage. The study shows that rolling temperature has the greatest influence on the final subgrain size, followed by the parameter Hm/L. The roll speed and roll temperature have little effect on the deformed subgrain size.