Experimental study of the effect of increasing technological plasticity during asymmetric rolling of aluminum alloys

Abstract. In this paper the effect of asymmetric rolling on the possibility of increasing the technological plasticity of aluminum alloys was investigated. The experimental research was carried out on a laboratory asymmetric rolling mill with an individual drive of the work rolls with the possibility of creating a speed ratio from 1.0 to 5.0. It was shown that the increase of speed ratio of the work rolls from 1.0 to 5.0 significantly reduce the rolling force in comparison with symmetric rolling. Rolling force decreased in 1.9 times for alloy AD33 (AA6061), in 2.3 times for alloy AMg6, in 3.2 times for alloy D16 (AA2024). At the same time the technological plasticity was increased. Technological plasticity characterizes the ability of a material to undergo higher thickness reductions without fracture under certain conditions of stress, temperature, and strain rate. In asymmetric rolling the thickness reduction was increased from 48 to 87% for alloy D16, from 50 to 59% for alloy AMg6, and from 40 to 75% for alloy AD33 in comparison with symmetric rolling. In all cases the samples had initially room temperature and were subjected only to deformation heating and friction heating. Extremely high thickness reduction (87%) was achieved by a single pass asymmetric rolling (at speed ratio 5.0) for alloy D16. It was found that the ductility of the alloy D16 was 12.3% after asymmetric rolling with a thickness reduction of 87% and without the use of annealing. This was approximately 2 times higher than the initial ductility (6.2%) of the same alloy in the initial annealed state and much higher than ductility (0.3%) after symmetric rolling. New technological schemes of sheet rolling of aluminum alloys with high ductility and increased technological plasticity have been developed.